tag:theconversation.com,2011:/au/topics/genetics-38/articlesGenetics – The Conversation2024-03-21T18:58:32Ztag:theconversation.com,2011:article/2195942024-03-21T18:58:32Z2024-03-21T18:58:32ZTreatments tailored to you: how AI will change NZ healthcare, and what we have to get right first<p>Imagine this: a novel virus is rapidly breaking out nationwide, resulting in an epidemic. The government introduces vaccination mandates and a choice of different vaccines is available. </p>
<p>But not everyone is getting the same vaccine. When you sign up for vaccination, you are sent a vial with instructions to send a sample of your saliva to the nearest laboratory. Just a few hours later you receive a message telling you which vaccine you should get. Your neighbour also signed up for vaccination. But their vaccine is different from yours. </p>
<p>Both of you are now vaccinated and protected, although each of you received your vaccines depending on “who you are”. Your genetics, age, gender, and myriad of other factors are captured in a “model” that predicts and determines the best option to protect you from the virus.</p>
<p>It all sounds a bit like science fiction. But since the <a href="https://www.genome.gov/human-genome-project">decoding of the human genome in 2003</a>, we have entered the age of precision prevention. </p>
<p>New Zealand has a long-standing newborn screening programme. This includes <a href="https://www.auckland.ac.nz/en/news/2023/11/30/newborn-genomic-sequencing-sick-babies.html">genome sequencing machines available nationwide</a> and a <a href="https://www.tewhatuora.govt.nz/our-health-system/genetic-health-service-nz/about/">genetic health service</a>. Programmes such as these open up the possibilities of public health genomics and precision public health for everyone.</p>
<p>The further expansion of these programmes, as well as the expansion of the use of artificial intelligence and machine learning to enable a shift to more personalised preventive care, will change how public health care is delivered.</p>
<p>At the same time, these developments raise wider concerns over individual choice versus the greater good, personal privacy, and who is responsible for the protection of New Zealanders and their health information.</p>
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<h2>What is precision prevention?</h2>
<p>Think of precision prevention (also known as personalised prevention) as public health action tailored to the individual rather than broader groups of society. </p>
<p>This targeted healthcare is achieved by balancing a range of variables (including your genes, life history and environment) with your risks (including everything that changes within you as you grow older). </p>
<p>While advances in genomics are making precision prevention possible, machine learning algorithms fuelled by our personal data have made it closer to a reality. </p>
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Read more:
<a href="https://theconversation.com/its-2030-and-precision-medicine-has-changed-health-care-this-is-what-it-looks-like-90539">It's 2030, and precision medicine has changed health care – this is what it looks like</a>
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<p>We generate data about ourselves every day – via social media, smartwatches and other wearable devices – helping to train algorithms to match medical prevention measures with individuals. </p>
<p>Combine all of these with AI-driven predictive modelling, and you have a system that can predict the current and future state of your health with an eerie level of accuracy, and <a href="https://www.forbes.com/sites/forbestechcouncil/2022/01/25/how-ai-could-predict-medical-conditions-and-revive-the-healthcare-system/?sh=362288726c47">help you take steps to prevent disease</a>. </p>
<h2>Safety and delay</h2>
<p>The Prime Minister’s Chief Science Advisor recently <a href="https://www.pmcsa.ac.nz/artificial-intelligence-2/ai-in-healthcare/">published a report</a> mapping out the landscape of artificial intelligence and machine learning in New Zealand over the next five years. </p>
<p>While the report authors didn’t specifically reference “precision prevention”, they did include examples of this approach, such as <a href="https://edition.cnn.com/2023/08/01/health/ai-breast-cancer-detection/index.html">computer vision augmented mammography</a>. </p>
<p>But as the report suggests, adoption tends to fall behind the pace of innovation in AI. Te Whatu Ora–Health New Zealand has also <a href="https://www.tewhatuora.govt.nz/our-health-system/digital-health/national-ai-and-algorithm-expert-advisory-group-naiaeag-te-whatu-ora-advice-on-the-use-of-large-language-models-and-generative-ai-in-healthcare/">not approved</a> emerging large language models and generative artificial intelligence tools as safe and effective for use in healthcare. </p>
<p>This means generative AI-driven precision prevention practices, such as conversational AI for public health messaging, may have to wait before they can be deemed safe to use. </p>
<h2>Move forward with caution</h2>
<p>There is much to be excited about the prospects of the use of artificial intelligence and machine learning in ushering in a new age of precision prevention and preventive health. But at the same time, we must temper this with caution. </p>
<p>Artificial intelligence and machine learning may increase access and utilisation of healthcare by lowering barriers to medical knowledge and reducing human bias. But government and medical agencies need to reduce barriers related to digital literacy and access to online platforms.</p>
<p>For those with limited access to online resources or who have limited digital literacy, the already existent inequity of access to care and health could worsen. </p>
<p>Artificial intelligence also has a <a href="https://arstechnica.com/gadgets/2023/04/generative-ai-is-cool-but-lets-not-forget-its-human-and-environmental-costs/">significant environmental impact</a>. <a href="https://arxiv.org/pdf/1906.02243.pdf">One study</a> found several common large AI models can emit over 270,000 tonnes of carbon dioxide during their life cycle.</p>
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Read more:
<a href="https://theconversation.com/these-scientists-are-using-dna-to-target-new-drugs-for-your-genes-medicine-made-for-you-part-1-131986">These scientists are using DNA to target new drugs for your genes – Medicine made for you part 1</a>
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<p>Finally, technology is a shifting landscape. Proponents of precision healthcare must be careful with children and marginalised communities and their access to resources. Maintaining privacy and choice is essential – everyone should be in a position to control what they share with the AI agents. </p>
<p>In the end, each of us is different, and we all have our different needs for our health and for our lives. Moving more people to preventive care through precision healthcare will reduce the financial burden on the health system. </p>
<p>But as the report from the prime minister’s chief science officer emphasises, machine learning algorithms are a nascent field. We need more public education and awareness before the technology becomes part of our everyday lives.</p><img src="https://counter.theconversation.com/content/219594/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arindam Basu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As New Zealand readies itself for AI-assisted medical treatment targeted to individuals, officials need to ensure the benefits outweigh the risks.Arindam Basu, Associate Professor, Epidemiology and Environmental Health, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2191402024-02-27T12:41:39Z2024-02-27T12:41:39ZCould a couple of Thai otters have helped the UK’s otter population recover? Our study provides a hint<p>Otter populations crashed in Britain around the 1960s from the lethal effects of chemical pollution in rivers and lakes – or so we thought. <a href="https://academic.oup.com/mbe/article/40/11/msad207/7275014">Our research</a> has looked more closely at what happened to otters in Britain over the last 800 years and has revealed a more complex picture. </p>
<p>Since Eurasian otters (<em>Lutra lutra</em>) are at the top of the aquatic food chain in Britain, any contamination consumed by their prey, and by the prey of their prey, <a href="https://pubs.acs.org/doi/10.1021/acs.est.1c05410">accumulates in otters</a>. So otters are particularly susceptible to any toxic chemicals in their environment. </p>
<p>Following the banning of many chemical pollutants, otter populations began to recover, and we now have otters in <a href="https://onlinelibrary.wiley.com/doi/10.1111/eva.13505">every county in Britain</a>. National otter surveys have been conducted in Wales, Scotland and England since 1977 and have helped to track population recovery. </p>
<p>However, we didn’t have a good grasp on what population sizes were like in the decades before this time. We only had anecdotal evidence that otter hunting was becoming less “successful” over time, and that both sightings and signs of otters were rarer. </p>
<h2>Otter population decline</h2>
<p>Our research shows that roughly between 1950 and 1970, an extreme population decline happened in the east of England, and a strong decline in south-west England. They were probably caused by chemical pollution. </p>
<p>In Scotland, otter populations showed a long-term, but smaller decline, which suggests less chemical pollution. There was a smaller population decline in Wales, which started around 1800, possibly linked to otter hunting and changes in how people shaped and used the landscape. </p>
<p>While both deal with DNA, genetics focuses on individual genes and their roles, while genomics examines the entire set of an organism’s DNA. Although there have been genetic studies of otters in Britain, our research was the first time genomics was used to study Eurasian otters anywhere in the world.</p>
<p>Working with scientists from the Smithsonian Conservation Biology Institute and the Wellcome Sanger’s Darwin Tree of Life project, we looked at the entire otter genome. The upgrade from genetics to genomics threw up a few surprises. </p>
<p>First, there was a mitochondrial DNA sequence found in the east of England, which was very different to the sequences in the rest of Britain. Mitochondrial DNA is a sequence of DNA found in a cell’s mitochondria, which is what generates the energy. Mitochondrial DNA is inherited only from the mother, while the rest of the DNA is a mix of both the mother’s and the father’s DNA.</p>
<p>Another <a href="https://www.tandfonline.com/doi/full/10.1080/19768354.2023.2283763">recent study</a> by our research group, in collaboration with colleagues in South Korea, suggested a divergence between these two lineages at least 80,000 years ago. Finding this mitochondrial lineage (that, based on our data, is otherwise restricted to Asia) in the UK was surprising. </p>
<p>Second, we found high levels of genetic diversity in the east of England. Normally, after an extreme population decline such as the one we identified in this area, genetic diversity decreases. Yet we saw much greater diversity here than in the population in Scotland, where there was no clear evidence for such a decline. </p>
<h2>Thai otters</h2>
<p>With a little detective work, we discovered that a pair of Eurasian otters (the same species that we have in the UK), were brought to Britain from Thailand in the 1960s. Populations of Eurasian otters range right across Europe and Asia. Although they are the same species, there are several genetically distinct subspecies, particularly in Asia. </p>
<p>It seems possible that these genetically different otters from Thailand bred with otters in the east of England. At the time of the population decline, when native UK populations were at their smallest, even a few individuals introduced into the population may have made a big difference. And they left unexpected marks on the genome. </p>
<p>We don’t know for sure if this is what happened, and we need to do more work to find out what effect this may have had on otters in the east of England. High genetic diversity is usually good for a population or species. But on the other hand, conservation often strives to maintain genetic differences between populations, rather than mixing distinct populations.</p>
<p>One way to find out more would be to compare the genome of a Eurasian otter from Thailand to the otters we see in the east of England. Unfortunately, it’s not that easy. Since the 1960s, otters in Thailand and across Asia have become increasingly rare. This is due to habitat loss, pollution and the illegal otter trade. So getting samples for genome sequencing is very difficult. It highlights the importance of conserving the species in Asia, despite population recoveries in Europe.</p>
<p>Our work shows the value of using modern genomic tools to look at the genetic diversity of a threatened species. The application of such tools can uncover surprising facts, even in supposedly well-studied species.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Frank Hailer receives funding from NERC and Dŵr Cymru Welsh Water. </span></em></p><p class="fine-print"><em><span>Elizabeth Chadwick receives funding from the UK Natural Environment Research Council and from the Environment Agency</span></em></p><p class="fine-print"><em><span>Sarah du Plessis receives funding from the UK Natural Environment Research Council and the Global Wales International Mobility Fund.</span></em></p>Research has revealed how British otters may have been able to recover from species loss in the 1950s with the help of otters from Asia.Frank Hailer, Senior Lecturer in Evolutionary Biology, Cardiff UniversityElizabeth Chadwick, Senior Lecturer at the School of Biosciences, Cardiff UniversitySarah du Plessis, PhD Candidate, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2210852024-02-22T20:50:27Z2024-02-22T20:50:27ZHow advanced genetic testing can be used to combat the illegal timber trade<p>According to <a href="https://www.interpol.int/Crimes/Environmental-crime/Forestry-crime">Interpol</a>, the organization dedicated to facilitating international police co-operation, between 15 per cent and 30 per cent of the world’s traded timber comes from illegal sources. This is an estimated annual value of US$51-152 billion dollars. </p>
<p>Illegal logging has serious consequences for the environment, the climate and the local livelihoods of the people who depend upon the affected forests. In turn, local governments are faced with losses in revenue, rising corruption and decreasing timber prices. These make it even more difficult for the legal forestry sector to remain competitive. </p>
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<a href="https://theconversation.com/illegal-logging-in-africa-is-a-threat-to-security-202291">Illegal logging in Africa is a threat to security</a>
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<p>Even in Canada, customers are unwittingly supporting this theft by buying timber with false declarations. In the face of such issues, Canadian researchers are currently developing a <a href="https://publications.gc.ca/site/eng/9.891853/publication.html">traceability system</a> employing genomic identification technologies to help tackle the trade in illegal timber. </p>
<h2>Stemming the flow</h2>
<p>To help address poaching, the United States expanded the pre-existing <a href="https://www.fws.gov/law/lacey-act">Lacey Act in 2008</a>. Originally designed to control the illegal trade of <a href="https://www.ucsusa.org/resources/lacey-acts-effectiveness">wildlife</a>, it was adapted to help tackle the trade in illegally harvested wood. The 2008 amendments to the Lacey Act decreased the importation of illegally harvested wood into the U.S. by approximately 32 to 44 per cent. </p>
<p>In Canada, similar regulations have been put in place to avoid the exploitation of species at risk including the <a href="https://www.laws-lois.justice.gc.ca/eng/acts/W-8.5/index.html">Wild Animal and Plant Protection and Regulation of International and Interprovincial Trade Act</a>. But how do we know if the declarations of a wood product are accurate or correctly reported? </p>
<p>In general, identification methods can be categorized into three groups: anatomical, analytical or molecular biological techniques — each with its <a href="https://doi.org/10.13140/RG.2.2.21518.79689">own set of advantages and limitations</a>. </p>
<p>Identification methods which use the aid of <a href="https://doi.org/10.46830/wrirpt.21.00067">microscope technology</a> look for distinct characteristics of the wood anatomy including tissues and cells. It is also the group of methods most commonly used.</p>
<p>However, this method requires trained specialists, the appropriate equipment and can typically only provide meaningful conclusions at the <a href="https://www.biologyonline.com/dictionary/genus">genus level</a>. In addition, wood anatomy cannot tell us where a piece of wood comes from. </p>
<h2>Looking to genetics</h2>
<p>This is where genomics come into play. To determine the species identity and the geographic origin of a logged tree, <a href="https://www.nature.com/articles/35016000">researchers take advantage of evolution</a>. </p>
<p>A few key factors make genetic identification possible. </p>
<p>Firstly, there are clear genetic differences between distinct <em><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2771874/#:%7E:text=We%20define%20a%20genetic%20species,from%20the%20Biological%20Species%20Concept.">species</a></em>. Secondly, the closer the relationship between individuals — in this case trees — the more genetically similar they are, while the more removed the individuals are the less genetic information is shared.</p>
<p>Therefore, it is possible to assign an individual to a “local population” based on its genetic fingerprint, sharing parts of its genetic makeup with that population and, consequently, <a href="https://pubs.cif-ifc.org/doi/abs/10.5558/tfc2018-010">also the specific region where it originates from</a>. This method is called population genetics. </p>
<p>The power of population genetics lies in its ability to identify groups of individuals that share a certain amount of genetic information that can be used to assign individuals to a species or a geographic region. The same methods can be used for humans to find unknown relatives or trace back the ethnic origin of your ancestors. </p>
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Read more:
<a href="https://theconversation.com/weakening-australias-illegal-logging-laws-would-undermine-the-global-push-to-halt-forest-loss-172770">Weakening Australia's illegal logging laws would undermine the global push to halt forest loss</a>
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<p>To reliably assign individuals, a variety of genetic markers is needed, varying between species and local populations. </p>
<p>In Canada, the first successful use of genetic material to conduct forensic testing on trees was pioneered by geneticist Eleanor White who succeeded in <a href="https://cfs.nrcan.gc.ca/pubwarehouse/pdfs/5177.pdf">tracing a wood log directly to the specific stump of an 800-year-old cedar tree in Western Canada</a> left behind after its illegal felling.</p>
<p>White’s success demonstrates the power of genomic identification in regulating the timber trade.</p>
<h2>Developing new systems</h2>
<p>Genomic sequencing in combination with genetic data analyses gained public traction during the COVID-19 pandemic, as these were used to <a href="https://doi.org/10.1038/s41467-020-18314-x">identify an outbreak of a new virus variant and trace its origin</a>.</p>
<p>Current research in wood forensics is using similar tools to assign an individual to a source population with high accuracy. Since genetic analyses can be costly, genetic databases of <a href="https://doi.org/10.1002/ppp3.10297">previously studied species</a> are compiled and used as test data to determine the best and most reliable analytical method.</p>
<p>The aim is to create a simple traceability system for timber products that border officials can implement quickly and easily. This should help stop the sale of illegally harvested timber and hold those responsible to account. </p>
<p>The long-term goal is to make it more difficult to sell illegally harvested timber in Canada and thus contribute to the protection of valuable forests. In addition, traceability can certify areas in Canada which are sustainably managed, making it easier for consumers to support sustainable forest management practices.</p><img src="https://counter.theconversation.com/content/221085/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Melanie Zacharias receives funding from Génome Québec. </span></em></p>Effective use of genomic identification could revolutionize the control of the illegal timber trade.Melanie Zacharias, Postdoctoral researcher in forest genetics, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230682024-02-20T19:37:25Z2024-02-20T19:37:25ZCanada’s Genetic Non-Discrimination Act has only had a limited impact on the use of genetic information by life insurers<figure><img src="https://images.theconversation.com/files/575694/original/file-20240214-20-o0yrke.jpg?ixlib=rb-1.1.0&rect=0%2C31%2C4256%2C2790&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Collecting genetic information for the purposes of determining life insurance protections could lead to genetic discrimination.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The advancement of genetic technologies in the past three decades has spotlighted the urgent need to address genetic discrimination. Genetic discrimination is the differential adverse treatment or unfair profiling of an individual relative to the rest of the population <a href="https://www.facetsjournal.com/doi/10.1139/facets-2023-0101">based on actual or presumed genetic information</a>. </p>
<p>If not regulated, genetic discrimination has the potential to infringe on people’s privacy and fundamental freedoms. This in turn may deter people from accessing clinical genetic services and testing based on concerns about how their personal information may be used.</p>
<p>Evidence from a growing number of countries shows that a person’s genetic information can be misused by third parties. A person may be refused employment or <a href="https://theconversation.com/life-insurers-can-charge-more-or-decline-cover-based-on-your-genetic-test-results-new-laws-must-change-this-212183">insurance</a> based on an assumption that they may develop a life-threatening disease.</p>
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<span class="caption">The widespread availability of genetic testing poses new risks for consumers.</span>
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<h2>New avenues for discrimination</h2>
<p>While instances of genetic discrimination have primarily arisen in the context of life insurance, the wider use of genetic testing and data usage in non-health settings has introduced new avenues for discrimination to occur. </p>
<p>Recently, genetic discrimination has taken on many forms, with reports emerging in <a href="https://doi.org/10.1177/0034523719869956">education</a>, access to <a href="https://ssrn.com/abstract=2973255">property</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/34366728">sports</a>, <a href="https://doi.org/10.1038/sj.ejhg.5201937">adoption</a> and <a href="https://doi.org/10.1097/hrp.0000000000000141">crime prevention</a>.</p>
<p>In an effort to prevent genetic discrimination and advance research, the Canadian Parliament adopted the <a href="https://laws-lois.justice.gc.ca/eng/annualstatutes/2017_3/page-1.html">Genetic Non-Discrimination Act</a> (GNDA) in 2017. Broadly understood, the GNDA prohibits the imposition and use of genetic test results as a condition to access goods and services. </p>
<p>The GNDA also makes “genetic characteristics” a prohibited ground for discrimination under the <a href="https://www.chrc-ccdp.gc.ca/en/node/723">Canadian Human Rights Act</a> and prohibits the use of genetic testing in matters of employment under the <a href="https://laws-lois.justice.gc.ca/eng/acts/l-2/page-34.html#:%7E:text=247.98%20(1)%20The%20following%20definitions%20apply%20in%20this%20Division.&text=(2)%20Every%20employee%20is%20entitled,to%20undergo%20a%20genetic%20test.&text=(3)%20Every%20employee%20is%20entitled,results%20of%20a%20genetic%20test.">Canadian Labour Code</a>.</p>
<p>After a series of revisions, debates and legal challenges, the GNDA was <a href="https://www.cbc.ca/news/politics/stefanovich-supreme-court-of-canada-genetic-information-1.5643245">finally confirmed in 2020 by the Supreme Court of Canada</a>.</p>
<h2>A modest impact</h2>
<p>Our research at McGill University’s <a href="https://www.genomicsandpolicy.org/">Centre of Genomics and Policy</a> investigated the impact of the GNDA. We focused on genetic discrimination in the context of purchasing life insurance coverage from private insurers — an area that has received significant attention in genetic discrimination literature. </p>
<p>We found that the <a href="https://www.facetsjournal.com/doi/full/10.1139/facets-2023-0101">GNDA has had only a modest impact</a> on <a href="https://www.usatoday.com/money/blueprint/insurance/what-is-insurance-underwriting/">the underwriting practices</a> of Canadian life insurance companies. The researchers reviewed 16 application forms, accounting for almost 50 per cent of the life insurance companies in Québec.</p>
<p>The study demonstrated that, while a small number of companies are taking steps to comply with the GNDA, the impact of the law on the industry as a whole has been limited. Only four companies explicitly stated that applicants should not submit genetic test results. </p>
<p>The study also confirmed that it is possible for life insurers to circumvent the law by asking broadly phrased questions regarding genetic information that would not qualify as “results,” prompting voluntary submission of genetic results.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a couple sit across from a doctor in a white coat" src="https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576095/original/file-20240215-26-m2z2lh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Life insurance companies sometimes solicit information in a manner that could prompt applicants to provide genetic information.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Preventing genetic discrimination</h2>
<p>While the GNDA marks an important first step in curtailing the spread of genetic discrimination, it appears that further steps will be necessary to prevent it. </p>
<p>Our study also raises fundamental questions about the opacity of the practices of the personal insurance industry in Canada, the limits of data protection legislation and the need to consider the potential discriminatory impact of third parties’ use of predictive health data in general. </p>
<p>We recommend the adoption of provincial regulations to provide more comprehensive protections, beyond those in the GNDA. Inclusive societal conversations and debate are also needed to further identify and design additional safeguards against discrimination. </p>
<p>Ultimately, given the lack of clarity around practices of insurers, there is a need for dialogue with the <a href="https://www.clhia.ca/">Canadian Life and Health Insurance Association</a> to encourage greater transparency around the underwriting process.</p><img src="https://counter.theconversation.com/content/223068/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Diya Uberoi receives funding from Genome Canada. </span></em></p><p class="fine-print"><em><span>Yann Joly receives funding from Genome Canada. </span></em></p>Canada needs additional regulation, developed through public consultations, stakeholder collaborations and community partnerships, to help regulate genetic testing and prevent genetic discrimination.Diya Uberoi, Academic Associate, Centre of Genomics and Policy, McGill UniversityYann Joly, James McGill Professor, Department of Human Genetics and Health Sciences, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2235492024-02-19T03:46:27Z2024-02-19T03:46:27ZScientists shocked to discover new species of green anaconda, the world’s biggest snake<figure><img src="https://images.theconversation.com/files/576419/original/file-20240219-26-4pucih.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5294%2C3532&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The green anaconda has long been considered one of the Amazon’s most <a href="https://content.time.com/time/specials/packages/article/0,28804,1916160_1916151_1916136,00.html">formidable and mysterious</a> animals. Our <a href="https://www.mdpi.com/1424-2818/16/2/127">new research</a> upends scientific understanding of this magnificent creature, revealing it is actually two genetically different species. The surprising finding opens a new chapter in conservation of this top jungle predator.</p>
<p>Green anacondas are the world’s heaviest snakes, and among the longest. Predominantly found in rivers and wetlands in South America, they are renowned for their lightning speed and ability to asphyxiate huge prey then swallow them whole.</p>
<p>My colleagues and I were shocked to discover significant genetic differences between the two anaconda species. Given the reptile is such a large vertebrate, it’s remarkable this difference has slipped under the radar until now. </p>
<p>Conservation strategies for green anacondas must now be reassessed, to help each unique species cope with threats such as climate change, habitat degradation and pollution. The findings also show the urgent need to better understand the diversity of Earth’s animal and plant species before it’s too late.</p>
<figure class="align-center ">
<img alt="snake on branches above water" src="https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576390/original/file-20240219-30-pwv50z.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientists discovered a new snake species known as the northern green anaconda.</span>
<span class="attribution"><span class="source">Bryan Fry</span></span>
</figcaption>
</figure>
<h2>An impressive apex predator</h2>
<p>Historically, four anaconda species have been recognised, including green anacondas (also known as giant anacondas).</p>
<p>Green anacondas are true behemoths of the reptile world. The largest females can grow to more than <a href="https://www.britannica.com/animal/anaconda#ref708759">seven metres long</a> and weigh <a href="https://taronga.org.au/news/2018-07-11/green-anaconda-weighs">more than 250 kilograms</a>.</p>
<p>The snakes are well-adapted to a life lived mostly in water. Their nostrils and eyes are on top of their head, so they can see and breathe while the rest of their body is submerged. Anacondas are olive-coloured with large black spots, enabling them to blend in with their surroundings.</p>
<p>The snakes inhabit the lush, intricate waterways of South America’s Amazon and <a href="https://www.britannica.com/place/Orinoco-Basin">Orinoco</a> basins. They are known for their stealth, patience and surprising agility. The buoyancy of the water supports the animal’s substantial bulk and enables it to move easily and leap out to ambush prey as large as capybaras (giant rodents), caimans (reptiles from the alligator family) and deer. </p>
<p>Green anacondas are not venomous. Instead they take down prey using their large, flexible jaws then crush it with their strong bodies, before swallowing it.</p>
<p>As apex predators, green anacondas are vital to maintaining balance in their ecosystems. This role extends beyond their hunting. Their very presence alters the behaviour of a wide range of other species, influencing where and how they forage, breed and migrate.</p>
<p>Anacondas are highly sensitive to environmental change. Healthy anaconda populations indicate vibrant ecosystems, with ample food resources and clean water. Declining anaconda numbers may be harbingers of environmental distress. So knowing which anaconda species exist, and monitoring their numbers, is crucial.</p>
<p>To date, there has been little research into genetic differences between anaconda species. Our research aimed to close that knowledge gap.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stop-killing-brown-snakes-they-could-be-a-farmers-best-friend-222142">Stop killing brown snakes – they could be a farmer's best friend</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="snake in water eating deer" src="https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576418/original/file-20240219-27-h8efx6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Green anaconda have large, flexible jaws. Pictured: a green anaconda eating a deer.</span>
<span class="attribution"><span class="source">JESUS RIVAS</span></span>
</figcaption>
</figure>
<h2>Untangling anaconda genes</h2>
<p>We studied representative samples from all anaconda species throughout their distribution, across nine countries.</p>
<p>Our project spanned almost 20 years. Crucial pieces of the puzzle came from samples we collected on a 2022 expedition to the Bameno region of Baihuaeri Waorani Territory in the Ecuadorian Amazon. We took this trip at the invitation of, and in collaboration with, Waorani leader Penti Baihua. Actor Will Smith also joined the expedition, as part of a series he is filming for National Geographic. </p>
<p>We surveyed anacondas from various locations throughout their ranges in South America. Conditions were difficult. We paddled up muddy rivers and slogged through swamps. The heat was relentless and swarms of insects were omnipresent. </p>
<p>We collected data such as habitat type and location, and rainfall patterns. We also collected tissue and/or blood from each specimen and analysed the samples back in the lab. This revealed the green anaconda, formerly believed to be a single species, is actually two genetically distinct species. </p>
<p>The first is the known species, <em>Eunectes murinus</em>, which lives in Perú, Bolivia, French Guiana and Brazil. We have given it the common name “southern green anaconda”. The second, newly identified species is <em>Eunectes akayima</em> or “northern green anaconda”, which is found in Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname and French Guiana.</p>
<p>We also identified the period in time where the green anaconda diverged into two species: almost 10 million years ago. </p>
<p>The two species of green anaconda look almost identical, and no obvious geographical barrier exists to separate them. But their level of genetic divergence – 5.5% – is staggering. By comparison, the genetic difference between humans and apes is <a href="https://www.scientificamerican.com/article/what-does-the-fact-that-w/#:%7E:text=Most%20studies%20indicate%20that%20when,size%20of%20the%20comparison%20unit.">about 2%</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-forgotten-amazon-as-a-critical-summit-nears-politicians-must-get-serious-about-deforestation-in-bolivia-205263">The forgotten Amazon: as a critical summit nears, politicians must get serious about deforestation in Bolivia</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="green anaconda underwater" src="https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576399/original/file-20240219-18-42nfsl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The two green anaconda species live much of their lives in water.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Preserving the web of life</h2>
<p>Our research has peeled back a layer of the mystery surrounding green anacondas. This discovery has significant implications for the conservation of these species – particularly for the newly identified northern green anaconda. </p>
<p>Until now, the two species have been managed as a single entity. But each may have different ecological niches and ranges, and face different threats. </p>
<p>Tailored conservation strategies must be devised to safeguard the future of both species. This may include new legal protections and initiatives to protect habitat. It may also involve measures to mitigate the harm caused by climate change, deforestation and pollution — such as devastating effects of <a href="https://news.mongabay.com/2023/05/critics-question-causes-behind-major-oil-spill-in-ecuadorian-amazon/">oil spills</a> on aquatic habitats. </p>
<p>Our research is also a reminder of the complexities involved in biodiversity conservation. When species go unrecognised, they can slip through the cracks of conservation programs. By incorporating genetic taxonomy into conservation planning, we can better preserve Earth’s intricate web of life – both the species we know today, and those yet to be discovered.</p><img src="https://counter.theconversation.com/content/223549/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Bryan G. Fry is a National Geographic Explorer and has previously received funding as part of this role.</span></em></p>Green anacondas are the world’s heaviest snakes, and among the longest. it’s remarkable this hidden species has slipped under the radar until now.Bryan G. Fry, Professor of Toxicology, School of the Environment, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225332024-02-14T16:55:57Z2024-02-14T16:55:57ZMen become less fertile with age, but the same isn’t true for all animals – new study<figure><img src="https://images.theconversation.com/files/573049/original/file-20240202-27-wscv4y.jpg?ixlib=rb-1.1.0&rect=0%2C34%2C5833%2C3938&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/colorful-balloons-spermatozoid-shape-on-blue-1100465771">olliulli/Shutterstock</a></span></figcaption></figure><p>We take it for granted that humans find it <a href="https://www.tandfonline.com/doi/full/10.3109/09513590.2010.501889">more difficult to conceive</a> as they grow older. But <a href="https://www.nature.com/articles/s41467-024-44768-4">our recent study</a>, which analysed data from 157 animal species, found that male reproductive ageing seems to be a lot less common in other male animals. </p>
<p>With fertility in men <a href="https://www.bmj.com/content/305/6854/609">declining worldwide</a>, understanding ageing of sperm in other animals could give new insights into our own fertility. </p>
<p>Human fertility declines with age because sperm and eggs of older people are <a href="https://academic.oup.com/humupd/article/11/3/261/759255">more deteriorated</a> or fewer in number than those of young people. Reproducing at an older age not only affects your fertility, but can also <a href="https://www.nature.com/articles/nrurol.2013.18">reduce the fertility</a>, survival rate and physical and cognitive performance of the children you conceive.</p>
<h2>Humans versus other animals</h2>
<p>Humans <a href="https://link.springer.com/article/10.1007/s00239-019-09896-2">live considerably longer</a> than we did just a century ago. This <a href="https://www.pnas.org/doi/full/10.1073/pnas.0909606106">recent, rapid extension</a> in our longevity might be one reason why humans reproductively age at faster rates than other animals. Our reproductive ageing rate hasn’t slowed down yet to match our longer lifespans. </p>
<p>Animals might also face greater evolutionary pressure to maximise their reproductive potential at all ages, because most animals reproduce throughout their lives. But this isn’t the case for humans. We rarely <a href="https://academic.oup.com/humrep/article/29/6/1304/625687">reproduce</a> in our late life. </p>
<p>Additionally, we have <a href="https://academic.oup.com/humrep/article/37/4/629/6515525">fewer offspring</a> compared to our ancestors. This makes it harder for natural selection to select genes that improve human reproduction due to less variation in the population’s fecundity. </p>
<h2>Females versus males</h2>
<p>Males and females in many species age reproductively at different rates. </p>
<p>For instance, in red wolves, male reproductive success declines with age but it <a href="https://link.springer.com/article/10.1007/s00265-016-2241-9">does not</a> for females. Yet female killifish show stronger decline in fertility with age <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2656.13382">than males</a>. Despite the fact human females live longer than males, they tend to become infertile <a href="https://www.science.org/doi/abs/10.1126/science.3755843">earlier than men</a>, and go through menopause. </p>
<p>In some species, including humans, where females help raise their grand-offspring (such as humans and whales), females live <a href="https://www.sciencedirect.com/science/article/pii/S0960982218316828?via%3Dihub">much beyond the age</a> of reproduction. An <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsos.191972">evolutionary explanation</a> for this is that older females can better pass on their genes by helping their relatives survive and rear young than by reproducing themselves.</p>
<p>There are some hypotheses that try to explain these <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/acel.13542">sex-specific differences</a> in reproductive ageing. </p>
<p>Sperm are continuously produced in males, but eggs in many species, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8769179/">including humans</a>, are produced early in the life of females. This might lead eggs to <a href="https://academic.oup.com/humupd/article/6/6/532/616993">accumulate more damage</a> due to being stored for longer durations inside older females than sperm are stored in old males. </p>
<p>Another hypothesis suggests that males might age faster because sperm DNA <a href="https://elifesciences.org/articles/80008">accumulate more</a> mutations than egg DNA. Sperm have poorer DNA repair machinery than eggs, causing males to <a href="https://www.nature.com/articles/s41586-023-05752-y">pass on more mutations</a> to the next generation than females with advancing age, a pattern observed across vertebrate animals.</p>
<p>Sexes also face different environmental pressures. For instance, in many mammals, males, <a href="https://theconversation.com/of-mice-and-matriarchs-the-female-led-societies-of-the-animal-kingdom-186875">but not females</a>, disperse away from the family group when they mature. This sort of environmental pressure leads to differences in the strategies males and females use to pass on their genes, which can create differences in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/acel.13542">rates of reproductive ageing</a> between the sexes. </p>
<figure class="align-center ">
<img alt="Humpback whale mother with her calf" src="https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573052/original/file-20240202-19-valjo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Female whales live long after their reproductive window.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/humpback-whale-mother-calf-on-tonga-1907017690">Tomas Kotouc/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Patterns of reproductive ageing in animals</h2>
<p>In our study, we showed that reproductive ageing rates in males <a href="https://www.nature.com/articles/s41467-024-44768-4">vary vastly</a> across the animal kingdom. We found invertebrates such as crustacea and insects have some of the slowest rates of reproductive ageing, compared to lab rodents who had some of the fastest rates.
Generally though, male animals showed few signs of age-related declines in their ejaculate traits (such as sperm quality and quantity). </p>
<p>We also found that different ejaculate traits, such as sperm viability, number, motility or velocity, aged at different rates.</p>
<p>In species that grow throughout their lives, such as some fish and crustacea, old animals have a lower mortality risk and larger gonads than young males. This can cause old males <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2021.2146">in such species</a> to age at slower rates, with older males producing larger ejaculates than younger males.</p>
<p>In animals such as lab rodents, who have some genetic lines selected for accelerated ageing, reproductive ageing was universal across ejaculate traits. Lab rodents are generally kept in highly controlled environments where ageing is easier to detect – due to fewer confounding effects that could mask ageing. This suggests that a lot of the variation in male reproductive ageing between different species could be due to their environment. </p>
<p>We also discovered that closely related species showed similar rates of decline in ejaculates with age, suggested that ageing is also shaped by an animal’s evolutionary history. </p>
<p>Some of the patterns we mention above also reflected methodological differences between studies. For example, when studies kept male animals as virgins, old males can <a href="https://www.pnas.org/doi/full/10.1073/pnas.2009053117">accumulate more sperm</a> than young males, leading to old males producing larger ejaculates. </p>
<p>Additionally, studies that only sampled young to middle-aged males showed an increase in sperm quality and quantity with age, compared to studies that sampled middle-aged to old males, suggesting that fertility peaks around middle age in male animals generally.</p>
<h2>Reproductive ageing</h2>
<p>Reproductive ageing occurs because as individuals grow older, their sperm and eggs <a href="https://www.nature.com/articles/nrurol.2013.18">accumulate damage</a>. Organisms have evolved to reproduce earlier in life rather than when old, which leads to a <a href="https://academic.oup.com/genetics/article/156/3/927/6051413">weaker ability of natural selection</a> to weed out bad genes that are expressed in old but not young organisms, in turn promoting ageing.</p>
<p>There are however, opposing forces that determine whether old individuals will leave more copies of their genes to successive lineages compared to young animals, and reproductive ageing is only one process determining this. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/bies.201100157">An alternative hypothesis</a> is that parents who conceive at an older age would have more gene variants for longer lifespans which could benefit their offspring. This could lead to longer lived offspring from older conceiving parents. However evidence for this hypothesis is still limited. </p>
<p>While most scientists accept that at least some reproductive traits decline with age, biologists are still uncovering what the exact mechanisms and evolutionary reasons for these declines are. But by looking at other species to investigate the drivers of reproductive ageing, we can understand and perhaps even seek to alleviate our own reproductive decline with age.</p><img src="https://counter.theconversation.com/content/222533/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Krish Sanghvi receives funding from Society for the study of evolution (Rosemary grant award).</span></em></p><p class="fine-print"><em><span>Irem Sepil receives funding from the Royal Society, BBSRC and Wellcome Trust. </span></em></p><p class="fine-print"><em><span>Regina Vega-Trejo receives funding from Biotechnology and Biological Sciences Research Council.</span></em></p>Understanding how the ageing of sperm works in other animals is more important than ever as human male fertility is in decline.Krish Sanghvi, PhD student at the department of Biology, University of Oxford, University of OxfordIrem Sepil, Lecturer in Evolutionary Biology, University of OxfordRegina Vega-Trejo, Postdoctoral Research Assistant in Evolutionary Biology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196832024-02-05T23:06:31Z2024-02-05T23:06:31ZGenetic diseases: How scientists are working to make DNA repair (almost) a piece of cake<figure><img src="https://images.theconversation.com/files/564984/original/file-20231101-27-722eas.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C992%2C561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An error in DNA is called a mutation.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>I have always been fascinated by genetics, a branch of biology that helps explain everything from the striking resemblance between different members of a family to the fact that strawberry plants are frost-resistant. It’s an impressive field!</p>
<p>I also have a personal connection to genetics. Growing up, I learned that members of my family had a form of <a href="https://doi.org/10.3390/jcm12186011">muscular dystrophy</a> called dysferlinopathy. I watched as my mother gradually lost the ability to climb stairs and had to use a cane, then a walker, and finally a wheelchair to get around. Her leg muscles were less and less able to repair themselves and became weaker with time.</p>
<p>My parents explained to me that all these changes were due to the error of a single letter among the billions of letters in a long DNA sequence. This error prevents the production of the protein <a href="https://doi.org/10.3390/jcm12144769">responsible for repairing arm and leg muscles</a>.</p>
<p>Today, I am a doctoral research student in molecular medicine. I study the treatment of hereditary diseases in order to be able to help families like my own. In this article, I will demystify hereditary diseases and show what research is being carried out to treat them.</p>
<h2>A piece of cake? Not quite</h2>
<p>Let’s start by imagining DNA as a recipe book. Each gene represents a different recipe. The page with the chocolate cake recipe has a nice picture, but there is some information missing. The recipe says to preheat the oven and measure the flour, but the rest of the page is torn. So it is impossible to make the cake. We go ahead and serve our meal made from all the other recipes, but there is no chocolate cake even though this is a particularly important part of the meal.</p>
<p>The same is true for hereditary diseases. In this case, the body can make all the proteins it needs except one. In dysferlinopathy, which affects my family, the missing recipe is the protein that repairs the muscles of the arms and legs. Each hereditary disease has its own damaged page in its recipe book.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580032/original/file-20240305-21577-nvf7ba.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A mutation can cause the absence of a protein that has its own function.</span>
<span class="attribution"><span class="source">(Camille Bouchard)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>To be precise, an error in the DNA is called a mutation. There are different types of mutations. Some are caused by adding letters, like adding an ingredient to the recipe. This addition could lead to a delicious chocolate cake with strawberries, or to a cake that is no longer edible because we added motor oil to it.</p>
<p>Other mutations are caused by the removal (or elimination) of one or more letters (or ingredients), or by substitutions that replace one letter with another. All of these modifications can lead to favourable or non-impactful changes, such as the appearance of the first blue eyes in evolution, or the ability to breathe outside of water. But these modifications can also bring about unfavourable results, such as a hereditary disease or cancer.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=616&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=616&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=616&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=774&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=774&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565888/original/file-20231214-19-3u3el2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=774&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There are different types of mutations.</span>
<span class="attribution"><span class="source">(Camille Bouchard)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>Repairing DNA</h2>
<p>From a young age, I understood that my mother was sick due to the error of a gene, but that I would not develop the disease because my father did not have the same error. This is called a recessive disease, since there must be an error in the gene of each of the two parents in order for the disease to manifest. Other hereditary diseases are dominant, meaning that a mutation in the DNA passed down from just one parent is enough to impair the production of a protein.</p>
<p>As part of my research, I look at the DNA sequence of each dysferlinopathy patient to see where the error is.</p>
<p>To try to correct it, I use <a href="https://doi.org/10.3390/cells12040536">Prime editing</a>, a technique which makes it possible to cut the DNA near the mutation and rewrite the sequence correctly. Prime editing is a version of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4975809/">CRISPR-Cas9</a>, a technique that allows DNA to be cut at a particular location.</p>
<p>Prime editing uses a protein called Cas9, which occurs naturally in bacteria. This protein allows bacteria to destroy the DNA sequences of viruses that could infect them. The mission of the Cas9 protein is to recognize a sequence and cut it.</p>
<p>When we use Cas9 in our human cells, we attach it to another protein, which rewrites the DNA sequence based on a template. In other words, we give the cell an error-free sequence so that it can go ahead and manufacture the protein on its own. It’s a bit like recovering the original page of the recipe book so you can finally serve the chocolate cake.</p>
<h2>A step in the right direction</h2>
<p>So why aren’t we hearing about Prime editing, when it could be used to treat a variety of diseases? Because the technology is not yet fully developed. At the moment we are able to repair DNA directly in cells in the laboratory, but we lack the means to deliver the two large proteins (Cas9 and the one that rewrites) to the cells to be treated (for example, to the centre of the affected muscles).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565889/original/file-20231214-21-z2b726.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Prime editing is a technique being studied to correct mutations in different genes.</span>
<span class="attribution"><span class="source">(Camille Bouchard)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>In other words, we have found the chocolate cake recipe, but it’s written on a page that is too large to fit in an email or put in an envelope. Many laboratories, including mine, are looking for an efficient and safe vehicle that will be able to deliver these proteins.</p><img src="https://counter.theconversation.com/content/219683/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camille Bouchard received funding from the Jain Foundation and the Fondation du CHU de Québec.</span></em></p>Many people know someone with a genetic disease, but few understand how gene mutations work.Camille Bouchard, Étudiante au doctorat en médecine moléculaire (correction génétique de maladies héréditaires), Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2206292024-01-31T13:36:25Z2024-01-31T13:36:25Z‘Jaws’ portrayed sharks as monsters 50 years ago, but it also inspired a generation of shark scientists<figure><img src="https://images.theconversation.com/files/572002/original/file-20240129-17-8m3oe7.jpg?ixlib=rb-1.1.0&rect=37%2C0%2C4952%2C3261&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A paleontologist wears a T-shirt showing _Strophodus rebecae_, a shark species with flat teeth that lived millions of years ago.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/palaeontologist-edwin-cadena-shows-a-t-shirt-with-an-image-news-photo/1241210531">Juan Pablo Pino/AFP via Getty Images</a></span></figcaption></figure><p>Human fear of sharks has deep roots. Written works and art from the ancient world contain references to <a href="https://www.artmajeur.com/en/magazine/5-art-history/sharks-in-art/331942">sharks preying on sailors</a> as early as the eighth century B.C.E. </p>
<p>Relayed back to land, stories about shark encounters have been <a href="https://etc.usf.edu/lit2go/42/moby-dick/747/chapter-66-the-shark-massacre/">embellished and amplified</a>. Together with the fact that from time to time – very rarely – sharks bite humans, people have been primed for centuries to imagine terrifying situations at sea.</p>
<p>In 1974, Peter Benchley’s <a href="https://www.penguinrandomhouse.ca/books/11203/jaws-by-peter-benchley/9780345544148/excerpt">bestselling novel “Jaws</a>” fanned this fear into a wildfire that spread around the world. The book sold more than 5 million copies in the U.S. within a year and was quickly followed by <a href="https://www.imdb.com/title/tt0073195/">Steven Spielberg’s 1975 movie</a>, which became the highest-grossing film in history at that time. Virtually all audiences embraced the idea, depicted vividly in the movie and its sequels, that sharks were malevolent, vindictive creatures that prowled coastal waters seeking to feed on unsuspecting bathers. </p>
<p>But “Jaws” also spawned widespread interest in better understanding sharks. </p>
<p>Previously, shark research had largely been the esoteric domain of a handful of academic specialists. Thanks to interest sparked by “Jaws,” we now know that there are many more kinds of sharks than scientists were aware of in 1974, and that sharks do more interesting things than researchers ever anticipated. Benchley himself became an avid <a href="https://www.latimes.com/archives/la-xpm-2006-feb-13-me-benchley13-story.html">spokesman for shark protection and marine conservation</a>.</p>
<p>In my own 30-year career studying <a href="https://scholar.google.com/citations?user=FKrC4FYAAAAJ&hl=en">sharks and their close relatives, skates and rays</a>, I’ve seen attitudes evolve and interest in understanding sharks expand enormously. Here’s how things have changed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&rect=32%2C8%2C5434%2C3630&q=45&auto=format&w=1000&fit=clip"><img alt="A man stands on the prow of a boat, extending a pole into the water toward a large dark shape." src="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&rect=32%2C8%2C5434%2C3630&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Marine biologist Greg Skomal of the Massachusetts Division of Marine Fisheries captures video footage of a white shark off Cape Cod, Oct. 21, 2022.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dr-greg-skomal-shark-researcher-for-massachusetts-marine-news-photo/1244267691">Joseph Prezioso/AFP via Getty Images</a></span>
</figcaption>
</figure>
<h2>Swimming into the spotlight</h2>
<p>Before the mid-1970s, much of what was known about sharks came via people who went to sea. In 1958, the U.S. Navy established the <a href="https://www.floridamuseum.ufl.edu/shark-attacks/">International Shark Attack File</a> – the world’s only scientifically documented, comprehensive database of all known shark attacks – to reduce wartime risks to sailors stranded at sea when their ships sank. </p>
<p>Today the file is managed by the <a href="https://www.floridamuseum.ufl.edu/">Florida Museum of Natural History</a> and the <a href="https://elasmo.org/">American Elasmobranch Society</a>, a professional organization for shark researchers. It works to inform the public about shark-human interactions and ways to reduce the risk of shark bites.</p>
<p>In 1962, <a href="https://www.fisheries.noaa.gov/feature-story/john-jack-casey-internationally-recognized-shark-researcher-mentor-and-narragansett">Jack Casey</a>, a pioneer of modern shark research, initiated the <a href="https://www.fisheries.noaa.gov/resource/document/cooperative-shark-tagging-program">Cooperative Shark Tagging Program</a>. This initiative, which is still running today, relied on Atlantic commercial fishermen to report and return tags they found on sharks, so that government scientists could calculate how far the sharks had moved after being tagged. </p>
<p>After “Jaws,” shark research quickly went mainstream. The American Elasmobranch Society was founded in 1982. Graduate students lined up to study shark behavior, and the number of published shark studies <a href="https://thefisheriesblog.com/2015/06/15/thank-you-jaws-the-upside-for-sharks-40-years-later/">sharply increased</a>.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/reel/Cz6muU6u3Mn/?utm_source=ig_web_copy_link\u0026igsh=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Field research on sharks expanded in parallel with growing interest in extreme outdoor sports like surfing, parasailing and scuba diving. Electronic tags enabled researchers to monitor sharks’ movements in real time. DNA sequencing technologies provided cost-effective ways to determine how different species were related to one another, what they were eating and how populations were structured.</p>
<p>This interest also had a sensational side, embodied in the Discovery Channel’s launch in 1988 of <a href="https://www.discovery.com/shark-week">Shark Week</a>. This annual block of programming, ostensibly designed to educate the public about shark biology and counter negative publicity about sharks, was a commercial venture that exploited the tension between people’s deep-seated fear of sharks and their yearning to understand what made these animals tick. </p>
<p>Shark Week featured made-for-TV stories that focused on <a href="https://www.washingtonpost.com/news/arts-and-entertainment/wp/2018/07/26/a-fake-shark-week-documentary-about-megalodons-caused-controversy-why-is-discovery-bringing-it-up-again/">fictional scientific research projects</a>. It was wildly successful and remains so today, in spite of critiques from some researchers who call it <a href="https://theconversation.com/beware-of-shark-week-scientists-watched-202-episodes-and-found-them-filled-with-junk-science-misinformation-and-white-male-experts-named-mike-195180">a major source of misinformation</a> about sharks and shark science.</p>
<h2>Physical, social and genetic insights</h2>
<p>Contrary to the long-held notion that sharks are mindless killers, they exhibit a wide range of traits and behavior. For example, the velvet belly lantern shark communicates through flashes of light from <a href="https://doi.org/10.4161/cib.4.3.14888">organs on the sides of its body</a>. Female hammerhead sharks can <a href="http://dx.doi.org/10.1098/rsbl.2007.0189">clone perfect replicas of themselves</a> without male sperm. </p>
<p>Sharks have the most sensitive electrical detectors thus far discovered in the natural world – networks of pores and nerves in their heads, known as <a href="https://www.scienceandthesea.org/program/201105/ampullae-lorenzini">ampullae of Lorenzini</a>, after Italian scientist Stefano Lorenzini, who first described these features in the 17th century. Sharks use these networks to navigate in the open ocean, <a href="https://doi.org/10.1016/j.cub.2021.03.103">using Earth’s magnetic field for orientation</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three snorkelers swim above a large spotted shark." src="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Snorkelers swim above a whale shark near the Maldives in the Indian Ocean. The largest fish in the sea, whale sharks are filter feeders that prey on plankton.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/gTntz7">Tchami/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Another intriguing discovery is that some shark species, including makos and blue sharks, <a href="http://dx.doi.org/10.1098/rsbl.2008.0761">segregate by both sex and size</a>. Among these species, cohorts of males and females of different sizes are often found in distinct groups. This finding suggests that some sharks may have <a href="https://www.britannica.com/topic/hierarchy-social-science">social hierarchies</a>, like those seen in some primates and hoofed mammals. </p>
<p>Genetic studies have helped researchers explore questions such as why some sharks <a href="https://theconversation.com/why-do-hammerhead-sharks-have-hammer-shaped-heads-184372">have heads shaped like hammers or shovels</a>. They also show that sharks have the <a href="https://doi.org/10.1038/s41467-023-42238-x">lowest mutation rate of any vertebrate animal</a>. This is notable because mutations are the raw material for evolution: The higher the mutation rate, the better a species can adapt to environmental change. </p>
<p>However, sharks have been around for 400 million years and have been through some of the most extreme environmental changes on earth. It’s not known yet how they have persisted so successfully with such a low mutation rate.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/punSQuf-ZwQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gavin Naylor, director of the Florida Program for Shark Research, describes how DNA analysis provides insights into shark science.</span></figcaption>
</figure>
<h2>The marquee species</h2>
<p>White sharks, the focal species of “Jaws,” attract enormous public interest, although much about them is still unknown. They can live to age 70, and they routinely swim thousands of miles every year. Those in the Western North Atlantic tend to move north-south between Canada and the Gulf of Mexico; white sharks on the U.S. west coast move east-west between California and the Central Pacific. </p>
<p>We now know that juvenile white sharks feed almost exclusively on fishes and stingrays, and don’t start incorporating seals and other marine mammals into their diets until they are the equivalent of teenagers and have grown to about 12 feet long. Most confirmed white shark bites on humans seem to be by animals that are between 12 and 15 feet long. This supports the theory that almost all bites by white sharks on humans are <a href="https://doi.org/10.1098/rsif.2021.0533">cases of mistaken identity</a>, where humans resemble the seals that sharks prey on.</p>
<p><iframe id="9y7JJ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/9y7JJ/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Still in the water</h2>
<p>Although “Jaws” had a <a href="https://www.today.com/popculture/jaws-took-chomp-out-pop-culture-40-years-ago-1d79919594">widespread cultural impact</a>, it didn’t keep surfers and bathers from enjoying the ocean. </p>
<p>Data from the International Shark Attack File on confirmed unprovoked bites by white sharks from the 1960s to the present day shows a continuous increase, although the number of incidents yearly is quite low. This pattern is consistent with growing numbers of people <a href="https://coast.noaa.gov/states/fast-facts/tourism-and-recreation.html">pursuing recreational activities at the coasts</a>. </p>
<p>Around the world, there have been 363 <a href="https://www.floridamuseum.ufl.edu/shark-attacks/maps/world-interactive/">confirmed, unprovoked bites by white sharks</a> since 1960. Of these, 73 were fatal. The World Health Organization estimates that there are <a href="https://www.who.int/news-room/fact-sheets/detail/drowning">236,000 deaths yearly due to drowning</a>, which translates to around 15 million drowning deaths over the same time period. </p>
<p>In other words, people are roughly 200,000 times more likely to drown than to die from a white shark bite. Indeed, surfers are more likely to die in a car crash on the way to the beach than they are to be bitten by a shark.</p><img src="https://counter.theconversation.com/content/220629/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gavin Naylor receives funding from the National Science Foundation and the Lenfest Foundation.</span></em></p>‘Jaws,’ published in 1974, terrified the public of sharks, but it also brought shark research into the scientific mainstream.Gavin Naylor, Director of Florida Program for Shark Research, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201342024-01-22T13:32:06Z2024-01-22T13:32:06ZAlcohol and drugs rewire your brain by changing how your genes work – research is investigating how to counteract addiction’s effects<figure><img src="https://images.theconversation.com/files/569941/original/file-20240117-21-ycbpim.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3600%2C1810&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Alcohol and other drugs can overpower the reward pathways of the brain.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/illustration-of-a-brain-cocktail-isolate-don-a-royalty-free-image/1263367270">Simona Dumitru/Moment via Getty Images</a></span></figcaption></figure><p>Many people are wired to <a href="https://www.penguinrandomhouse.ca/books/306396/the-compass-of-pleasure-by-david-j-linden/9780143120759">seek and respond to rewards</a>. Your brain interprets food as rewarding when you are hungry and water as rewarding when you are thirsty. But addictive substances like alcohol and drugs of abuse can <a href="https://doi.org/10.1016/S2215-0366(16)00104-8">overwhelm the natural reward pathways</a> in your brain, resulting in intolerable cravings and reduced impulse control. </p>
<p>A popular misconception is that addiction is a result of low willpower. But an explosion of knowledge and technology in the field of <a href="https://plato.stanford.edu/entries/molecular-genetics/">molecular genetics</a> has changed our basic understanding of addiction drastically over the past decade. The general consensus among scientists and health care professionals is that there is a <a href="https://www.penguinrandomhouse.ca/books/557515/never-enough-by-judith-grisel/9780525434900">strong neurobiological and genetic basis</a> for addiction.</p>
<p>As a <a href="https://scholar.google.com/citations?user=XgunjGkAAAAJ&hl=en">behavioral neurogeneticist</a> <a href="https://www.kaunlab.com">leading a team</a> investigating the molecular mechanisms of addiction, I combine neuroscience with genetics to understand how alcohol and drugs influence the brain. In the past decade, I have seen changes in our understanding of the molecular mechanisms of addiction, largely due to a better understanding of how genes are dynamically regulated in the brain. New ways of thinking about how addictions form have the potential to change how we approach treatment.</p>
<h2>Alcohol and drugs affect brain gene activity</h2>
<p>Each of your brain cells has your genetic code stored in long strands of DNA. For all that DNA to fit into a cell, it needs to be packed tightly. This is achieved by winding the DNA around “spools” of protein <a href="https://www.genome.gov/genetics-glossary/histone">called histones</a>. Areas where DNA is unwound contain active genes coding for proteins that serve important functions within the cell.</p>
<p>When gene activity changes, the proteins your cells produce also change. Such changes can range from a single neuronal connection in your brain to how you behave. This genetic choreography suggests that while your genes affect how your brain develops, <a href="https://theconversation.com/brains-work-via-their-genes-just-as-much-as-their-neurons-47522">which genes are turned on or off</a> when you are learning new things is dynamic and adapts to suit your daily needs.</p>
<p>Recent data from animal models suggests that alcohol and drugs of abuse directly influence <a href="https://doi.org/10.1523/JNEUROSCI.1649-20.2020">changes in gene expression</a> in areas of the brain that help drive memory and reward responses. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram magnifying the nucleus of a neuron, showing spirals of DNA wound around bundles of protein" src="https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=449&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=449&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567627/original/file-20240103-29-mcair4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=449&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Within each neuron in the brain, how tightly DNA is wound around or bound to histones and other proteins determines which genes are expressed and which proteins are produced.</span>
<span class="attribution"><span class="source">Karla Kaun and Vinald Francis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>There are <a href="https://doi.org/10.1523/JNEUROSCI.1649-20.2020">many ways</a> addictive substances can change gene expression. They can alter which proteins bind to DNA to turn genes on and off and which segments of DNA are unwound. They can change the process of how DNA is read and translated into proteins, as well as alter the proteins that determine how cells use energy to function.</p>
<p>For example, alcohol can cause an alternative form of a gene to be expressed in the memory circuits <a href="https://doi.org/10.1534/genetics.120.303101">in flies</a> <a href="https://doi.org/10.1038/s41598-023-30926-z">and people</a>, resulting in changes in dopamine receptors and transcription factors involved in reward signaling and neuronal function. Similarly, cocaine can cause an alternative form of a gene to be expressed in the <a href="https://doi.org/10.1016/j.neuron.2021.08.008">reward centers</a> <a href="https://doi.org/10.1016/j.biopsych.2017.11.027">of mice</a>, leading them to seek out more cocaine.</p>
<p>Exactly how these drugs cause changes in gene regulation is unknown. However, a direct link between alcohol consumption and changes in gene expression in mice provides a clue. A byproduct of alcohol being broken down in the liver called acetate can cross the blood-brain barrier and <a href="https://doi.org/10.1038/s41586-019-1700-7">unwind DNA from histones</a> in mouse memory circuits. </p>
<p>Alcohol, nicotine, cocaine and opioids also all activate important signaling pathways that are <a href="https://doi.org/10.1111/jnc.12725">central regulators of metabolism</a>. This suggests they can also affect many aspects of neuronal function and consequently affect which genes are expressed.</p>
<h2>Changing brain gene activity with lifestyle</h2>
<p>How addictive substances change cell function is complex. The version of a gene you’re born with can be modified in many ways before it becomes a functional protein, including exposure to alcohol and drugs. Rather than discouraging researchers, this complexity is empowering because it provides evidence that changes to gene expression in your brain aren’t permanent. They can also be altered by medications and lifestyle choices.</p>
<p>Many commonly prescribed medications for mental health disorders also affect gene expression. <a href="https://doi.org/10.1038%2Fs41398-019-0589-0">Antidepressants and</a> <a href="https://doi.org/10.1016/j.jpsychires.2013.05.028">mood stabilizers</a> can change how DNA is modified and which genes are expressed. For example, a commonly prescribed drug for depression called escitalopram affects how tightly wound DNA is and can change the expression of genes important to brain plasticity.</p>
<p>Additionally, <a href="https://theconversation.com/customizing-mrna-is-easy-and-thats-what-makes-it-the-next-frontier-for-personalized-medicine-a-molecular-biologist-explains-216127">mRNA-based therapies</a> can specifically change which genes are expressed to treat diseases like cancer. In the future, we may discover similar therapies for alcohol and substance use disorder. These treatments could potentially target important <a href="https://doi.org/10.1016%2Fj.tins.2021.09.006">signaling pathways linked to addiction</a>, altering how brain circuits function and how alcohol and drugs affect them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of person sitting with crossed legs on a yoga mat, hands resting on knees with pointer finger touching thumb" src="https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569945/original/file-20240117-29-n459lb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exercise and other lifestyle choices can affect gene regulation.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/indonesian-woman-is-meditating-in-a-half-lotus-royalty-free-image/1391023941?adppopup=true">Afriandi/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p>Lifestyle choices can also affect gene expression in your brain, though researchers don’t yet know whether they can alter the changes induced by addictive substances. </p>
<p>Like alcohol and drugs, <a href="https://theconversation.com/what-you-eat-can-reprogram-your-genes-an-expert-explains-the-emerging-science-of-nutrigenomics-165867">dietary changes</a> can affect gene expression in many ways. In flies, a high sugar diet can <a href="https://doi.org/10.1126/sciadv.abc8492">reprogram the ability to taste sweetness</a> by tapping into a gene expression network involved in development.</p>
<p><a href="https://doi.org/10.1016/j.cpnec.2022.100152">Intensive</a> <a href="https://doi.org/10.1016/j.psyneuen.2013.11.004">meditation</a>, even after only <a href="https://doi.org/10.1016/j.bbi.2019.11.003">one day</a>, can also affect gene regulation in your brain through similar mechanisms. Attending a <a href="https://doi.org/10.1016/j.cpnec.2022.100152">monthlong meditation retreat</a> reduces the expression of genes that affect inflammation, and experienced meditators can reduce inflammatory genes after just <a href="https://doi.org/10.1016/j.bbi.2019.11.003">one day of intensive meditation</a>. </p>
<p>Work in animal models has also shown that exercise changes gene expression by altering both <a href="https://doi.org/10.1016/j.brainres.2020.147191">histones</a> <a href="https://doi.org/10.1016/j.molmet.2021.101398">and the</a> <a href="https://doi.org/10.1111/j.1460-9568.2010.07508.x">molecular tags</a> directly attached to DNA. This increases the activity of genes important to the activity and plasticity of neurons, supporting the idea that <a href="https://theconversation.com/high-intensity-exercise-improves-memory-and-wards-off-dementia-127001">exercise improves learning and memory</a> and can decrease the risk of dementia.</p>
<p>From <a href="https://doi.org/10.1037/hea0000297">Dry January</a> and beyond, many factors can have profound effects on your brain biology. Taking steps to reduce consumption of alcohol and drugs and picking up healthy lifestyle practices can help stabilize and bring long-lasting benefits for your physical and mental health.</p><img src="https://counter.theconversation.com/content/220134/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karla Kaun receives funding from the National Institute on Alcohol Abuse and Alcoholism, the National Institute on Drug Abuse and the National Institute of General Medical Sciences.</span></em></p>Improved understanding of the molecular mechanisms of addiction can change how researchers and clinicians approach treatments.Karla Kaun, Associate Professor of Neuroscience, Brown UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196202024-01-18T16:38:26Z2024-01-18T16:38:26ZDNA from stone age chewing gum sheds light on diet and disease in Scandinavia’s ancient hunter-gatherers<figure><img src="https://images.theconversation.com/files/570142/original/file-20240118-27-aehxwa.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C464%2C352&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A mold cast of one of the chewed pitch pieces.</span> <span class="attribution"><span class="source">Verner Alexandersen</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Some 9,700 years ago on an autumn day, a group of people were camping on the west coast of Scandinavia. They were hunter-gatherers that had been fishing, hunting and collecting resources in the area. </p>
<p>Some teenagers, both boys and girls, were chewing resin to produce glue, just after eating trout, deer and hazelnuts. Due to a severe gum infection (periodontitis), one of the teenagers had problems eating the chewy deer-meat, as well as preparing the resin by chewing it.</p>
<p>This snapshot of the Mesolithic period, just before Europeans started farming, comes from analysis of DNA left in the chewed resin that we have conducted, now <a href="https://www.nature.com/articles/s41598-023-48762-6">published in Scientific Reports</a>. </p>
<p>The location is now known as <a href="https://lup.lub.lu.se/search/publication/3c1fd58a-9495-4403-ab7d-d22104f2fafb">Huseby Klev</a>, situated north of Gothenburg (Göteborg), Sweden. <a href="https://www.cambridge.org/core/journals/antiquity/article/abs/wet-and-the-wild-followed-by-the-dry-and-the-tame-or-did-they-occur-at-the-same-time-diet-in-mesolithic-neolithic-southern-sweden/D91F7830FE704FD24DFAFB55E551039B">It was excavated</a> by archaeologists in the early 1990s, and yielded some 1,849 flint artefacts and 115 pieces of resin (mastic). The site has been radiocarbon dated to between 10,200 and 9,400 years ago, with one of the pieces of resin dated to 9,700 years ago.</p>
<p>Some of the resin has teeth imprints, indicating that children, actually teenagers, had been chewing them. Masticated lumps, often with imprints of teeth, fingerprints or both, are not uncommon to find in Mesolithic sites. </p>
<p>The pieces of resin we have analysed were made of <a href="https://www.nature.com/articles/s41467-019-13549-9">birch bark pitch</a>, which is known to have been used as an <a href="https://phys.org/news/2019-08-neanderthal-tool-making-simpler-previously-thought.html">adhesive substance in stone tool technology</a> from the Middle Palaeolithic onward. However, they were also chewed for recreational or medicinal purposes in traditional societies.</p>
<p>A variety of substances with similar properties, such as resins from coniferous trees, natural bitumen, and other plant gums, are known to have been used in analogous ways in many parts of the world.</p>
<h2>The power of DNA</h2>
<p>In some of the resin, half the <a href="https://www.nature.com/articles/s42003-019-0399-1">DNA extracted</a> was of human origin. This is a lot compared to what we often find in ancient bones and teeth. </p>
<p>It represents some of the oldest human genomes from Scandinavia. It has a particular ancestry profile common among Mesolithic hunter gatherers who once lived there. </p>
<p>Some of the resin contains male human DNA while others have female DNA. We think that teenagers of both sexes were preparing glue for use in tool making, such as attaching a stone axe to a wooden handle.</p>
<p>But what of the other half of the DNA that was of non-human origin? Most of this DNA is from organisms such as bacteria and fungi that have lived in the mastic since it was discarded 9,700 years ago. But some of it was from bacteria living in the human that chewed it, along with material the human had been chewing on before they put the birch bark pitch in their mouths.</p>
<p>Analysing all this DNA is a demanding task and treads new ground. We had to both adapt existing computing tools and also develop some new analytical strategies. As such, this work has become the starting point for developing a new workflow for this kind of analysis. </p>
<p>This includes mining the DNA using different strategies to characterise it, trying to piece together short DNA fragments into longer ones and using machine learning techniques to work out which DNA fragments belong to pathogens (harmful microorganisms). It also involves comparing the data to what we see in the mouths of modern people with <a href="https://www.ncbi.nlm.nih.gov/books/NBK551699/">tooth decay (caries)</a> and periodontitis.</p>
<h2>Higher organisms</h2>
<p>Naturally, we found the kind of bacteria that would be expected in an oral microbiome, the range of naturally occurring microorganisms found in the mouth. We also found traces of bacteria implicated in conditions such as tooth decay or caries (<em>Streptococcus mutans</em>), and systemic diseases such as Hib disease and endocarditis. There were also bacteria that can cause abscesses. </p>
<p>Although these pathogenic microorganisms were present at an elevated frequency, they were not clearly above the level expected for a healthy oral microbiome. There is thus no conclusive evidence that members of the group suffered from diseases these microorganisms are associated with. </p>
<p>What we did find, however, was an abundance of bacteria associated with serious gum disease – <a href="https://www.mayoclinic.org/diseases-conditions/periodontitis/symptoms-causes/syc-20354473">periodontitis</a>. When we applied a <a href="https://www.ibm.com/topics/machine-learning">machine learning</a> strategy (in this case, a technique called <a href="https://www.ibm.com/topics/random-forest">Random Forest modelling</a>) we reached the conclusion that the girl who chewed one of the pieces of resin had probably suffered from periodontitis – with more than a 75% probability.</p>
<p>We also found DNA from larger organisms than just bacteria. We found DNA for red deer, brown trout and hazelnuts. This DNA probably came from material the teenagers had been chewing before they put the birch pitch in their mouths. </p>
<p>However, we need to be a little bit cautious because exactly what we find is also dependent on the comparison data that we have. As genomes from eukaryotic organisms – the group that includes plants and animals – <a href="https://www.ncbi.nlm.nih.gov/books/NBK9846/">are larger and more complex</a> than those from microorganisms, it is more complicated to assemble a eukaryotic genome of high quality. </p>
<p>There are fewer eukaryotic genomes in the samples of resin, and they are of lower quality. This means that our brown trout, for example, may not actually be a brown trout, but we at least feel certain it is from the salmon family.</p>
<p>We also found a lot of fox DNA, but this is harder to interpret. Fox meat may have been a part of the diet, but these teenagers could also have chewed on tendons and fur from foxes for use in textiles. Alternatively, the fox DNA could even be from territorial marking and got into the resin after it was spat out.</p>
<p>However, what we have learned for sure represents a big step in understanding these fascinating records of human culture from the Stone Age. As we analyse more of these, even more surprises could emerge.</p><img src="https://counter.theconversation.com/content/219620/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anders Götherström receives funding from: the Swedish Research Council (2019-00849_VR), Riksbankens Jubileumsfond (P16-0553:1)</span></em></p><p class="fine-print"><em><span>Emrah Kırdök does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Genetic analysis reveals one of the teenagers probably had advanced gum disease.Anders Götherström, Professor in Molecular Archaeology, Department of Archaeology and Classical Studies, Stockholm UniversityEmrah Kırdök, Assistant Professor, Department of Biotechnology, Mersin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207562024-01-09T20:18:23Z2024-01-09T20:18:23ZWhy don’t fruit bats get diabetes? New understanding of how they’ve adapted to a high-sugar diet could lead to treatments for people<figure><img src="https://images.theconversation.com/files/568452/original/file-20240109-23-jjo6l0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2376%2C1442&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fruit bats have honed their sweet tooth through adaptive evolution.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fruit-bat-feeding-in-a-tree-royalty-free-image/1293525000">Keith Rose/iStock via Getty Images Plus</a></span></figcaption></figure><p>People around the world eat too much sugar. When the body is unable to process sugar effectively, leading to excess glucose in the blood, this can result in diabetes. According to the World Health Organization, diabetes became the <a href="https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death">ninth leading cause of death</a> in 2019.</p>
<p>Humans are not the only mammals that love sugar. Fruit bats do, too, eating up to <a href="https://dem.ri.gov/sites/g/files/xkgbur861/files/programs/bnatres/fishwild/outreach/critter-kits/bat-ex-benefits.pdf">twice their body weight</a> in sugary fruit a day. However, unlike humans, fruit bats thrive on a sugar-rich diet. They can <a href="https://doi.org/10.1007/s00360-019-01242-8">lower their blood sugar faster</a> than bats that rely on insects as their main food source.</p>
<p>We are a team of <a href="https://www.menlo.edu/about/find-an-expert/wei-gordon/">biologists</a> and <a href="https://scholar.google.com/citations?user=kkrPGvcAAAAJ&hl=en">bioengineers</a>. Determining how fruit bats evolved to specialize on a high-sugar diet sent us on a quest to approach diabetes therapy from an unusual angle – one that sent us all the way to Lamanai, Belize, for the <a href="https://www.batcon.org/belize-bat-a-thon/">Belize Bat-a-thon</a>, an annual gathering where researchers collect and study bats.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people wearing face masks, one with a headlamp and one holding a small bat up to the camera" src="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Authors Nadav Ahituv, left, and Wei Gordon.</span>
<span class="attribution"><span class="source">Wei Gordon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In our <a href="https://doi.org/10.1038/s41467-023-44186-y">newly published research</a> in Nature Communications, we and colleagues <a href="https://netbiolab.org/w/People:SB_Baek">Seungbyn Baek</a> and <a href="https://scholar.google.com/citations?user=H4jO_DQAAAAJ&hl=en">Martin Hemberg</a> used a technology that analyzes the DNA of individual cells to compare the unique metabolic instructions encoded in the genome of the Jamaican fruit bat, <em>Artibeus jamaicensis</em>, with those in the genome of the insect-eating big brown bat, <em>Eptesicus fuscus</em>. </p>
<p><a href="https://doi.org/10.1038/nature11247">Approximately 2% of DNA</a> is composed of genes, which are segments of DNA that contain the instructions cells use to create certain traits, such as a <a href="https://doi.org/10.1016/j.acthis.2020.151503">longer tongue in fruit bats</a>. The other 98% are segments of DNA that regulate genes and determine the presence and absence of the traits they encode.</p>
<p>To understand how fruit bats evolved to consume so much sugar, we wanted to identify the genetic and cellular differences between bats that eat fruit and bats that eat insects. Specifically, we looked at the genes, regulatory DNA and cell types in two significant organs involved in metabolic disease: the pancreas and the kidney. </p>
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<a href="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four male *Artibeus jamaicensis* and four male *Eptesicus fuscus* bats were put in a fast then fed fruit or worms, respectively, or no meal before analyzing the cells and genes of their kidney and pancreas." src="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=306&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=306&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=306&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This flowchart outlines the authors’ study methodology.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41467-023-44186-y">Wei Gordon, created with BioRender.com/Nature Communications</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1038/s41580-020-00317-7">The pancreas</a> regulates blood sugar and appetite by secreting hormones like insulin, which lowers your blood sugar, and glucagon, which raises your blood sugar. We found Jamaican fruit bats have <a href="https://doi.org/10.1038/s41467-023-44186-y">more insulin-producing and glucagon-producing cells</a> than big brown bats, along with regulatory DNA that primes fruit bat pancreatic cells to initiate production of insulin and glucagon. Together these two hormones work to keep blood sugar levels balanced even when the fruit bats are eating large amounts of sugar.</p>
<p><a href="https://doi.org/10.1093%2Fndt%2Fgfx027">The kidney</a> filters metabolic waste from the blood, maintains water and salt balance and regulates blood pressure. Fruit bat kidneys need to be equipped to remove from their bloodstreams the large amounts of water that come from fruit while retaining the low amounts of salt in fruit. We found Jamaican fruit bats have adjusted the compositions of their kidney cells in accordance with their diet, <a href="https://doi.org/10.1038/s41467-023-44186-y">reducing the number of urine-concentrating cells</a> so their urine is more diluted with water compared with big brown bats.</p>
<h2>Why it matters</h2>
<p>Diabetes is one of the most expensive chronic conditions in the world. The <a href="https://doi.org/10.2337/dci23-0085">U.S. spent US$412.9 billion</a> in 2022 on direct medical costs and indirect costs related to diabetes.</p>
<p>Most approaches to developing new treatments for diabetes are based on traditional laboratory animals such as mice because they are easy to reproduce and study in a lab. But outside the lab, there exist mammals like fruit bats that have actually evolved to withstand high sugar loads. Figuring out how these mammals deal with high sugar loads can help researchers identify new approaches to treat diabetes.</p>
<p>By applying new cell characterization technologies on these <a href="https://theconversation.com/e-coli-is-one-of-the-most-widely-studied-organisms-and-that-may-be-a-problem-for-both-science-and-medicine-206045">nonmodel organisms</a>, or organisms researchers don’t usually use for research in the lab, we and a growing body of researchers show that nature could be leveraged to develop novel treatment approaches for disease. </p>
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<figcaption><span class="caption">The authors disentangle a fruit bat from a net during the Belize Bat-a-thon.</span></figcaption>
</figure>
<h2>What still isn’t known</h2>
<p>While our study revealed many potential therapeutic targets for diabetes, more research needs to be done to demonstrate whether our fruit bat DNA sequences can help understand, manage or cure diabetes in humans.</p>
<p>Some of our fruit bat findings may be unrelated to metabolism or are specific only to Jamaican fruit bats. There are <a href="https://www.britannica.com/animal/Old-World-fruit-bat">close to 200 species</a> of fruit bats. Studying more bats will help researchers clarify which fruit bat DNA sequences are relevant for diabetes treatment. </p>
<p>Our study also focused only on bat pancreases and kidneys. Analyzing other organs involved in metabolism, such as the liver and small intestine, will help researchers more comprehensively understand fruit bat metabolism and design appropriate treatments.</p>
<h2>What’s next</h2>
<p>Our team is now testing the regulatory DNA sequences that allow fruit bats to eat so much sugar and checking whether we can use them to better regulate how people respond to glucose.</p>
<p>We are doing this by <a href="https://www.youtube.com/watch?v=Cv59sjupd1Y&t=77s">swapping the regulatory DNA sequences</a> in mice with those of fruit bats and testing their effects on how well these mice manage their glucose levels.</p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p><img src="https://counter.theconversation.com/content/220756/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wei Gordon receives funding from NSF. </span></em></p><p class="fine-print"><em><span>Nadav Ahituv is a cofounder and on the scientific advisory board of Regel Therapeutics and also received funding from BioMarin Pharmaceutical Incorporate.
Funding for this research was supported by the National Human Genome Research Institute grant R01HG012396.
</span></em></p>Fruit bats can eat up to twice their body weight in fruit a day. But their genes and cells evolved to process all that sugar without any health consequences − a feat drug developers can learn from.Wei Gordon, Assistant Professor of Biology, Menlo CollegeNadav Ahituv, Professor, Department of Bioengineering and Therapeutic Sciences; Director, Institute for Human Genetics, University of California, San FranciscoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2188102023-12-21T19:08:14Z2023-12-21T19:08:14ZWhat octopus DNA tells us about Antarctic ice sheet collapse<figure><img src="https://images.theconversation.com/files/563522/original/file-20231205-29-pymbyu.jpg?ixlib=rb-1.1.0&rect=17%2C26%2C5973%2C3961&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>If we want to understand the future, it’s often useful to look at the past. And even more useful if you use octopus DNA to peer into worlds long gone. </p>
<p>About 125,000 years ago, the Earth was in its last warm period between ice ages. Global average temperatures during this interglacial period were about 0.5–1.5°C warmer than pre-industrial levels. </p>
<p>This has strong parallels with our time. For a <a href="https://www.bbc.com/news/science-environment-66857354">third of 2023</a>, the Earth’s temperature has been 1.5°C warmer than the pre-industrial era, driven by climate change. </p>
<p>For <a href="https://www.nature.com/articles/271321a0">almost 50 years</a> physical scientists have sought the answer to whether or not the vast West Antarctic Ice Sheet collapsed the last time global temperatures were this high. Rather than relying only on geological sampling, we turned to the DNA of a small Antarctic octopus for clues to the deep past. </p>
<p>The DNA had an answer. Our <a href="https://science.org/doi/10.1126/science.ade0664">new research</a> shows yes, it most likely collapsed. </p>
<p>The West Antarctic Ice Sheet is <a href="https://www.science.org/doi/10.1126/science.aaz5487">very susceptible to warming</a>. If it melts, it has enough water to raise global sea levels by 3.3 to 5 metres.</p>
<h2>Of octopuses and giant ice sheets</h2>
<p>Sediment records and other ice cores show us that the ice sheet retreated at some point during the last ~1 million years in the late Pleistocene, but the exact timing and extent of any collapse remain ambiguous.</p>
<p>To get a more precise answer, we looked to cephalopod genetics. </p>
<p>Every organism’s DNA is a history book, and we now have the technology to read it. We can use DNA to look back in time and pinpoint when different populations of animals were interbreeding. </p>
<p>Turquet’s octopus (<em>Pareledone turqueti</em>) is fairly small, weighing up to 600 grams. They live on the seafloor all around Antarctica, but individuals don’t move far from home. Antarctica is so vast that populations in different regions cannot usually interbreed. </p>
<p>Deep under West Antarctica lies gaps in the rocks. At present, these are filled by the ice sheet, making the Weddell, Amundsen and Ross seas separate from each other. </p>
<p>If the ice melted, seaways would open up and connect these isolated basins. Octopuses could directly migrate into these regions and the evidence of their breeding would be laid down in DNA. </p>
<p>But if the ice sheet didn’t melt, we would only see evidence of breeding between octopus populations along the circumference of the continent.</p>
<p>We compared DNA patterns in Turquet octopus genomes all around Antarctica to see if there were direct and unique connections between octopus populations in the Weddell, Amundsen and Ross seas. We used statistical models to figure out if these connections could be explained by their present day connections around the Antarctic coastline.</p>
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Read more:
<a href="https://theconversation.com/we-can-still-prevent-the-collapse-of-the-west-antarctic-ice-sheet-if-we-act-fast-to-keep-future-warming-in-check-215878">We can still prevent the collapse of the West Antarctic ice sheet – if we act fast to keep future warming in check</a>
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<p>The story was clear in the DNA: yes, there had been direct connections between these three octopus populations. Their connections could not be statistically explained by interbreeding around the present day Antarctic coastline. These populations could only come into contact through seaways now blocked by the West Antarctic Ice Sheet. </p>
<p>Even more interesting, we first found direct connections between the three populations during the mid-Pliocene, 3 million to 3.6 million years ago when temperatures were 2–3°C hotter and sea levels 25m higher than today. This supports <a href="https://www.nature.com/articles/nature07867">existing geological evidence</a> that the West Antarctic Ice Sheet collapsed during that era. </p>
<p>The most recent DNA signatures of direct connections between the octopuses of these three seas was during the last interglacial period around 125,000 years ago. That suggests the ice sheet collapsed when the global average temperature was around 1.5°C hotter than pre-industrial levels.</p>
<p>Our work provides the first empirical evidence the West Antarctic Ice Sheet could begin to collapse if we exceed the Paris Agreement goal of limiting warming to 1.5°C or even 2°C. </p>
<h2>This discovery took effort across disciplines and countries</h2>
<p>To use animal DNA as a proxy for changes in the ice sheet, we had to work across disciplines and countries. Bringing together physical scientists and biologists gave rise to new ways to answer long standing questions of vital importance to all of us. </p>
<p>We also turned to museum collections for samples. Some dated back three decades – well before the genetic sequencing and analytical techniques we used were available. This demonstrates the vital importance of careful sample preservation, linked with metadata, with specimens protected for future access.</p>
<p>Interdisciplinary science is hard. It requires time, effort, and an open mind to appreciate new terminologies, scales and approaches. Journal editors and scientists can be reluctant to review such papers, as some aspects of the research will necessarily be outside the area of their expertise. But we hope our results show the value of this approach. </p>
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<figcaption><span class="caption">The Antarctic seafloor is covered in marine life. Many of their ancestors also lived through climate changes in the past.</span></figcaption>
</figure>
<h2>What’s next?</h2>
<p>We hope to continue using DNA as a proxy to explore other parts of Antarctica with poorly understood climate histories. </p>
<p>There is a <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.16356">wealth of information</a> on Antarctica’s recent and distant past also hidden in other types of biological data in moss beds and peat profiles, vertebrate animal colonies and living terrestrial and marine invertebrates. To date, very few of these biological archives have been brought into our understanding of Antarctica’s past climates. </p>
<p>As the world heats up at an unprecedented rate, we need to use these types of approaches to understand what else is likely to happen down on the ice. </p>
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Read more:
<a href="https://theconversation.com/increasing-melting-of-west-antarctic-ice-shelves-may-be-unavoidable-new-research-216030">Increasing melting of West Antarctic ice shelves may be unavoidable – new research</a>
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<img src="https://counter.theconversation.com/content/218810/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sally Lau receives funding from the Australian Research Council (ARC). </span></em></p><p class="fine-print"><em><span>Jan Strugnell receives funding from the Australian Research Council (ARC), the Fisheries Research and Development Corporation (FRDC), the Department of Agriculture Water and the Environment through the National Environmental Science Program (NESP) and the Queensland Government through the Queensland Citizen Science Grants.</span></em></p><p class="fine-print"><em><span>Nerida Wilson receives funding from the Australian Research Council (ARC), Interact for Change and the Morris Animal Foundation (Wild Genomes).</span></em></p>Did the enormous West Antarctic Ice Sheet collapse the last time global temperatures were 1.5°C above preindustrial levels? The answer lay in the DNA of an octopus.Sally Lau, Postdoctoral Research Fellow, James Cook UniversityJan Strugnell, Professor Marine Biology and Aquaculture, James Cook UniversityNerida Wilson, Adjunct Senior Research Fellow, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196632023-12-14T13:19:15Z2023-12-14T13:19:15ZWe think we have found a cause of pregnancy sickness, and it may lead to a treatment<figure><img src="https://images.theconversation.com/files/565507/original/file-20231213-19-swroox.jpg?ixlib=rb-1.1.0&rect=48%2C0%2C5351%2C3540&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pregnancy sickness is believed to affect 7 in 10 women. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-suffering-morning-sickness-bathroom-home-1041217495">Monkey Business Images/Shutterstock</a></span></figcaption></figure><p>Sickness in pregnancy, or hyperemesis gravidarum, is common and is thought to <a href="https://journals.lww.com/obgynsurvey/abstract/2013/09001/the_impact_of_nausea_and_vomiting_of_pregnancy_on.1.aspx">affect</a> seven out of ten women at some time in their pregnancy. But, until recently, very little has been known about why it happens. </p>
<p><a href="https://www.nature.com/articles/s41586-023-06921-9">New research</a> by our team has identified sensitivity to a hormone made in abundance by the developing pregnancy, GDF15, as a contributor to the risk of pregnancy sickness.</p>
<p>This condition can affect pregnant women’s quality of life, even in so-called mild cases. Between 1% and 3% of women <a href="https://pubmed.ncbi.nlm.nih.gov/31515515/">suffer</a> from a severe form of pregnancy sickness when nausea and vomiting are so severe that they lose weight or become dehydrated, or both. In one study, this condition was the most common reason that women were admitted to <a href="https://pubmed.ncbi.nlm.nih.gov/12100809/">hospital</a> in the first three months of pregnancy. </p>
<p>It has been <a href="https://onlinelibrary.wiley.com/doi/10.1111/ppe.12416">associated</a> with worse pregnancy outcomes and its effect lasts beyond the end of pregnancy with some women <a href="https://pubmed.ncbi.nlm.nih.gov/21635201/">reporting</a> psychological distress and being reluctant to <a href="https://pubmed.ncbi.nlm.nih.gov/28241811/">conceive again</a>. </p>
<p>The fact that it develops in early pregnancy and invariably resolves when pregnancy ends strongly suggests that the cause of the sickness comes from the developing pregnancy. But the detail on how and why it happens has remained elusive. This dearth of understanding makes the development of treatments difficult and arguably contributes to the considerable <a href="https://www.pregnancysicknesssupport.org.uk/documents/research%20papers/stigma-of-hg.pdf">stigma</a> associated with this condition. </p>
<h2>GDF15</h2>
<p>GDF15 is a hormone that suppresses food intake in mice by acting, probably exclusively, on a small group of cells at the base of the brain which are also known to induce nausea and vomiting. As such, GDF15 has been under investigation as an <a href="https://pubmed.ncbi.nlm.nih.gov/36754014/">obesity therapy</a>. </p>
<p>Early trials confirm it suppresses appetite in people, but it also causes <a href="https://pubmed.ncbi.nlm.nih.gov/36630958/">nausea and vomiting</a>. It has long been known that it is abundant in human placenta and is present at very high concentrations in the blood of healthy pregnant women. These factors make it a plausible cause, but a detailed understanding of if GDF15 affects the severity of sickness in pregnancy has been lacking. </p>
<p>We used a variety of methods to study how GDF15 increases the risk of pregnancy sickness. We measured GDF15 in the blood of pregnant women attending hospital due to sickness and those attending hospital for other reasons. </p>
<p>We found that women with pregnancy sickness did indeed have higher levels of GDF15. While this was in keeping with GDF15 contributing to the condition, levels of GDF15 in each group overlapped substantially. This suggests that factors other than the absolute amount of GDF15 coming from the developing pregnancy might determine the risk of sickness.</p>
<p>Natural variation in DNA of future mothers contributes to risk of pregnancy sickness. Previous <a href="https://pubmed.ncbi.nlm.nih.gov/29563502/">studies</a> have identified changes in DNA near GDF15 as the biggest determinants of risk of pregnancy sickness. In particular, one rare genetic mutation (present in around one in 1,500 people) that affects the make-up of the GDF15 protein in the blood, has a large <a href="https://pubmed.ncbi.nlm.nih.gov/35218128/">effect</a> on that risk. </p>
<p>To understand the potential impact of this genetic variant on GDF15 levels in the bloodstream, we studied its effects on the protein in lab-grown cells. We discovered that this mutated GDF15 molecule gets stuck inside cells. What’s more, it actually stuck to and trapped “normal” GDF15 – this creates a double hit that hinders the transport of GDF15 out of cells. Healthy people with this mutation have markedly lower levels of GDF15 in their blood, which is consistent with these findings.</p>
<figure class="align-center ">
<img alt="A pregnant woman sits on the edge of a bed clutching her bump." src="https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565574/original/file-20231213-21-z851cx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Between 1% and 3% of women suffer from a severe form of pregnancy sickness.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pregnant-woman-sitting-on-bed-holding-310309151">Monkey Business Images/Shutterstock</a></span>
</figcaption>
</figure>
<p>We discovered that DNA changes near GDF15, which are prevalent in about 15 to 30% of people, lower the levels of the hormone. These changes increase the risk of pregnancy sickness by small amounts. Conversely, women with the blood disorder <a href="https://www.nhs.uk/conditions/thalassaemia/">thalassaemia</a>, who have very high levels of GDF15 throughout life, actually reported much less nausea and vomiting in pregnancy.</p>
<h2>A roadmap to treatment</h2>
<p>The conclusion of these studies is clear –- predisposition to higher levels of GDF15 when not pregnant reduces the risk of pregnancy sickness. At first glance, this is rather perplexing because how can having higher levels of a hormone that makes you sick protect against pregnancy sickness? </p>
<p>In fact, several hormone systems exhibit a phenomenon resembling memory, where the sensitivity to a hormone is influenced by previous exposure to that hormone. This seemed like the most plausible explanation for our results. Supporting this theory, mice with persistently high levels of GDF15 in their bloodstream were relatively unresponsive to an acute surge in GDF15 levels. </p>
<p>Our findings suggest that lower levels of GDF15 before pregnancy result in women being hypersensitive to the large amounts of GDF15 being released from the developing pregnancy. This poses two obvious approaches to treatment of this condition –- desensitising women to GDF15 by increasing its levels before pregnancy or blocking its action during pregnancy. </p>
<p>The challenge now is to develop and test strategies to achieve these aims that are safe and acceptable to women at risk from this debilitating condition.</p><img src="https://counter.theconversation.com/content/219663/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sam Lockhart is supported by a Wellcome Trust Clinical PhD Fellowship (225479/Z/22). SL is a named creator of a pending patent application relating to therapy for hyperemesis gravidarum filed by Cambridge Enterprise Limited (GB application No. 2304716.0; Inventor: Professor Stephen O’Rahilly.</span></em></p><p class="fine-print"><em><span>Stephen O'Rahilly has undertaken remunerated consultancy work for Pfizer, Third Rock Ventures, AstraZeneca, NorthSea Therapeutics and Courage Therapeutics. Part of the work in this paper is the subject of a pending patent application relating to therapy for hyperemesis gravidarum filed by Cambridge Enterprise Limited (GB application No. 2304716.0; Inventor: Professor Stephen O’Rahilly). SL and NR are named creators on this patent.</span></em></p>New research has uncovered the hormone that triggers morning sickness, offering hope for millions of women.Sam Lockhart, Wellcome Trust Clinical PhD Fellow, Institute of Metabolic Science and Medical Research Council Metabolic Diseases Unit, University of CambridgeStephen O'Rahilly, Professor and Co-Director of the Institute of Metabolic Science and Director of the Medical Research Council Metabolic Diseases Unit, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2113962023-11-29T13:38:49Z2023-11-29T13:38:49ZMicroRNA is the master regulator of the genome − researchers are learning how to treat disease by harnessing the way it controls genes<figure><img src="https://images.theconversation.com/files/561973/original/file-20231127-27-vqtw0l.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1400&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">RNA is more than just a transitional state between DNA and protein.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/molecule-of-mrna-illustration-royalty-free-illustration/1450368774">Kateryna Kon/Science Photo Library via Getty Images</a></span></figcaption></figure><p>The Earth <a href="https://www.scientificamerican.com/article/evolution-of-earth/">formed 4.5 billion years ago</a>, and life less than a billion years after that. Although life as we know it is <a href="https://sciencing.com/abundant-organic-compound-earth-22851.html">dependent on four major macromolecules</a> – DNA, RNA, proteins and lipids – only one is thought to have been present at the beginning of life: RNA. </p>
<p>It is no surprise that <a href="https://www.khanacademy.org/science/ap-biology/natural-selection/origins-of-life-on-earth/a/rna-world">RNA likely came first</a>. It is the only one of those major macromolecules that can both replicate itself and catalyze chemical reactions, both of which are essential for life. Like DNA, RNA is made from individual nucleotides linked into chains. Scientists initially understood that genetic information flows in one direction: DNA is transcribed into RNA, and RNA is translated into proteins. That principle is called the <a href="https://www.genome.gov/genetics-glossary/Central-Dogma">central dogma of molecular biology</a>. But there are many deviations.</p>
<p>One major example of an exception to the central dogma is that some RNAs are never translated or coded into proteins. This fascinating diversion from the central dogma is what led me to <a href="https://scholar.google.com/citations?user=4JMQMLgAAAAJ&hl=en">dedicate my scientific career</a> to understanding how it works. Indeed, research on RNA has lagged behind the other macromolecules. Although there are multiple classes of these so-called noncoding RNAs, researchers like myself have started to focus a great deal of attention on short stretches of genetic material called <a href="https://www.ibiology.org/genetics-and-gene-regulation/introduction-to-micrornas/">microRNAs</a> and their potential to treat various diseases, including cancer.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/t5jroSCBBwk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">MicroRNAs play a key role in regulating gene expression.</span></figcaption>
</figure>
<h2>MicroRNAs and disease</h2>
<p>Scientists regard microRNAs as <a href="https://doi.org/10.1146/annurev-pharmtox-010510-100517">master regulators of the genome</a> due to their ability to bind to and alter the expression of many protein-coding RNAs. Indeed, a single microRNA can regulate anywhere from 10 to 100 protein-coding RNAs. Rather than translating DNA to proteins, they instead can bind to protein-coding RNAs to silence genes. </p>
<p>The reason microRNAs can regulate such a diverse pool of RNAs stems from their ability to bind to target RNAs they don’t perfectly match up with. This means a single microRNA can often regulate a pool of targets that are all involved in similar processes in the cell, leading to an enhanced response.</p>
<p>Because a single microRNA can regulate multiple genes, many microRNAs can contribute to disease when they become dysfunctional.</p>
<p>In 2002, researchers first identified the role dysfunctional microRNAs play in disease through patients with a type of blood and bone marrow cancer called <a href="https://doi.org/10.1073/pnas.242606799">chronic lymphocytic leukemia</a>. This cancer results from the <a href="https://doi.org/10.1038/cdd.2009.69">loss of two microRNAs</a> normally involved in blocking tumor cell growth. Since then, scientists have identified <a href="https://mirbase.org/browse/results/?organism=hsa">over 2,000 microRNAs in people</a>, many of which are altered in various diseases. </p>
<p>The field has also developed a fairly solid understanding of how microRNA dysfunction contributes to disease. Changing one microRNA can change several other genes, resulting in a plethora of alterations that can collectively reshape the cell’s physiology. For example, over half of all cancers have significantly reduced activity in a <a href="https://doi.org/10.3389/fcell.2021.640587">microRNA called miR-34a</a>. Because miR-34a regulates many genes involved in preventing the growth and migration of cancer cells, losing miR-34a can increase the risk of developing cancer.</p>
<p>Researchers are looking into using microRNAs as therapeutics for cancer, heart disease, neurodegenerative disease and others. While results in the laboratory have been promising, bringing microRNA treatments into the clinic has <a href="https://doi.org/10.1016/j.tig.2022.02.006">met multiple challenges</a>. Many are related to inefficient delivery into target cells and poor stability, which limit their effectiveness.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram showing a loop of microRNA binding to a strand of mRNA as it's being translated from DNA" src="https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561975/original/file-20231127-26-jqjjuh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">MicroRNA can silence genes by binding to mRNA.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Conceptual_overview_of_multiomics_-_digital_skewed.png">Kajsa Mollersen/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Delivering microRNA to cells</h2>
<p>One reason why delivering microRNA treatments into cells is difficult is because microRNA treatments need to be delivered specifically to diseased cells while avoiding healthy cells. Unlike <a href="https://theconversation.com/how-mrna-and-dna-vaccines-could-soon-treat-cancers-hiv-autoimmune-disorders-and-genetic-diseases-170772">mRNA COVID-19 vaccines</a> that are taken up by scavenging immune cells whose job is to detect foreign materials, microRNA treatments need to fool the body into thinking they aren’t foreign in order to avoid immune attack and get to their intended cells.</p>
<p>Scientists are studying various ways to deliver microRNA treatments to their specific target cells. One method garnering a great deal of attention relies on directly <a href="https://doi.org/10.1093/narcan/zcab030">linking the microRNA to a ligand</a>, a kind of small molecule that binds to specific proteins on the surface of cells. Compared with healthy cells, diseased cells can have a disproportionate number of some surface proteins, or receptors. So, ligands can help microRNAs home specifically to diseased cells while avoiding healthy cells. The first ligand approved by the U.S. Food and Drug Administration to deliver small RNAs like microRNAs, <a href="https://doi.org/10.1007/s40265-020-01269-0">N-acetylgalactosamine, or GalNAc</a>, preferentially delivers RNAs to liver cells.</p>
<p>Identifying ligands that can deliver small RNAs to other cells requires finding receptors expressed at high enough levels on the surface of target cells. Typically, <a href="https://doi.org/10.1038/nrd4519">over one million copies per cell</a> are needed in order to achieve sufficient delivery of the drug.</p>
<p>One ligand that stands out is <a href="https://theconversation.com/adding-folic-acid-to-staple-foods-can-prevent-birth-defects-but-most-countries-dont-do-it-55533">folate, also referred to as vitamin B9</a>, a small molecule critical during periods of rapid cell growth such as fetal development. Because some tumor cells have over one million folate receptors, this ligand provides sufficient opportunity to deliver enough of a therapeutic RNA to target different types of cancer. For example, my laboratory developed a new molecule <a href="https://doi.org/10.1126/scitranslmed.aam9327">called FolamiR-34a</a> – folate linked to miR-34a – that reduced the size of breast and lung cancer tumors in mice.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image juxtaposing endothelial cells sprouting extensions to form new blood vessels and a cell bathed in microRNA unable to sprout" src="https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561976/original/file-20231127-18-5pbfrd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tumors can exploit healthy cells to grow blood vessels that provide them nutrients, as seen in the endothelial cells to the left sprouting extensions. Exposing these cells to certain microRNAs, however, can disable that growth, as seen in the cell to the right.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/2hrJ3g4">Dudley Lab, University of Virginia School of Medicine/NIH via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Making microRNAs more stable</h2>
<p>One of the other challenges with using small RNAs is their <a href="https://doi.org/10.1093/narcan/zcab030">poor stability</a>, which leads to their rapid degradation. As such, RNA-based treatments are generally short-lived in the body and require frequent doses to maintain a therapeutic effect. </p>
<p>To overcome this challenge, researchers are <a href="https://doi.org/10.1093/narcan/zcab030">modifying small RNAs</a> in various ways. While each RNA requires a specific modification pattern, successful changes can <a href="https://doi.org/10.1038/s41388-023-02801-8">significantly increase their stability</a>. This reduces the need for frequent dosing, subsequently decreasing treatment burden and cost. </p>
<p>For example, <a href="https://doi.org/10.1089%2Fnat.2018.0736">modified GalNAc-siRNAs</a>, another form of small RNAs, reduces dosing from every few days to once every six months in nondividing cells. My team developed <a href="https://doi.org/10.1038/s41388-023-02801-8">folate ligands</a> linked to modified microRNAs for cancer treatment that reduced dosing from once every other day to once a week. For diseases like cancer where cells are rapidly dividing and quickly diluting the delivered microRNA, this increase in activity is a significant advancement in the field. We anticipate this accomplishment will facilitate further development of this folate-linked microRNA as a cancer treatment in the years to come.</p>
<p>While there is still considerable work to be done to overcome the hurdles associated with microRNA treatments, it’s clear that RNA shows promise as a therapeutic for many diseases.</p><img src="https://counter.theconversation.com/content/211396/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea Kasinski receives funding from the National Institutes of Health, Department of Defense, and the American Lung Association. Kasinski is also the inventor on multiple patients associated with her discoveries in the RNA therapeutics field. </span></em></p>When just one of the thousands of microRNAs in people go awry, it can cause diseases ranging from heart disease to cancer.Andrea Kasinski, Associate Professor of Biological Sciences, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163262023-11-09T13:32:30Z2023-11-09T13:32:30ZCranberries can bounce, float and pollinate themselves: The saucy science of a Thanksgiving classic<figure><img src="https://images.theconversation.com/files/558166/original/file-20231107-21-cmo43c.jpg?ixlib=rb-1.1.0&rect=15%2C9%2C2029%2C1140&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cranberries grow on vines in sandy bogs and marshes.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/Mm6QhN">Lance Cheung, USDA/Flickr</a></span></figcaption></figure><p>Cranberries are a staple in U.S. households at Thanksgiving – but how did this bog dweller end up on holiday tables? </p>
<p>Compared to many valuable plant species that were domesticated over thousands of years, cultivated cranberry (<em>Vaccinium macrocarpon</em>) is a young agricultural crop, just as the U.S. is a young country and Thanksgiving is <a href="https://theconversation.com/how-advertising-shaped-thanksgiving-as-we-know-it-86819">a relatively new holiday</a>. But <a href="https://soilcrop.tamu.edu/people/desalvio-serina/">as a plant scientist</a>, I’ve learned much about cranberries’ ancestry from their botany and genomics.</p>
<h2>New on the plant breeding scene</h2>
<p>Humans have cultivated <a href="https://doi.org/10.1007/s10437-018-9314-2">sorghum for some 5,500 years</a>, <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=114445">corn for around 8,700 years</a> and <a href="https://doi.org/10.1534/g3.120.401362">cotton for about 5,000 years</a>. In contrast, cranberries were domesticated around 200 years ago – but people were eating the berries before that.</p>
<p>Wild cranberries are native to North America. They were an important food source for Native Americans, who used them in puddings, sauces, breads and a <a href="https://www.cranberries.org/exploringcranberries/into/maki_back.html">high-protein portable food called pemmican</a> – a carnivore’s version of an energy bar, made from a mixture of dried meat and rendered animal fat and sometimes studded with dried fruits. Some tribes <a href="https://lakotarednations.com/2017/11/wo-lakota-making-wasna/">still make pemmican today</a>, and even <a href="https://tankabar.com/">market a commercial version</a>. </p>
<p>Cranberry cultivation began in 1816 in Massachusetts, where Revolutionary War veteran Henry Hall found that <a href="https://www.youtube.com/watch?v=nt7NA7G808Y&t=5s">covering cranberry bogs with sand</a> fertilized the vines and retained water around their roots. From there, the fruit spread throughout the U.S. Northeast and Upper Midwest. </p>
<p>Today, <a href="https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=102649">Wisconsin produces roughly 60%</a> of the U.S. cranberry harvest, followed by Massachusetts, Oregon and New Jersey. Cranberries also are grown in Canada, where they are <a href="https://canadianfoodfocus.org/in-season/whats-in-season-cranberries/">a major fruit crop</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four men in waders, holding long rakes, thigh-deep in a flooded bog, its surface covered with floating cranberries." src="https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=305&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=305&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=305&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=383&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=383&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558168/original/file-20231107-29-f3xdq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=383&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Farmers often flood cranberry bogs to harvest the fruit, which they rake loose from the vines.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/bBmqts">Michael Galvin, Massachusetts Office of Travel and Tourism/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A flexible and adaptable plant</h2>
<p>Cranberries have many interesting botanical features. Like roses, lilies and daffodils, cranberry flowers are hermaphroditic, which means they <a href="https://www.gardeningknowhow.com/garden-how-to/info/hermaphroditic-plant-information.htm">contain both male and female parts</a>. This allows them to self-pollinate instead of relying on birds, insects or other pollinators. </p>
<p>A cranberry blossom has four petals that peel back when the flower blooms. This exposes the anthers, which contain the plant’s pollen. The flower’s resemblance to the beak of a bird earned the cranberry its original name, <a href="https://gobotany.nativeplanttrust.org/species/vaccinium/macrocarpon/">the “craneberry</a>.” </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A flower with four curved white petals tinged with pink." src="https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=742&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=742&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=742&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=932&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=932&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558169/original/file-20231107-23-zvban6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=932&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A blossom on a cranberry bush in Wisconsin.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cranberry_Blossom_%289180939392%29.jpg">Aaron Carlson/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>When cranberries don’t self-pollinate, they rely on bumblebees and honeybees to transport their pollen from flower to flower. They can also be propagated sexually, by planting seeds, or asexually, through rooting vine cuttings. This is important for growers because seed-based propagation allows for higher genetic diversity, which can translate to things like increased disease resistance or more pest tolerance. </p>
<p>Asexual reproduction is equally important, however. This method allows growers to create clones of varieties that perform very well in their bogs and grow even more of those high-performing types.</p>
<p>Every cranberry <a href="https://www.wisfarmer.com/story/news/2018/07/13/farm-technology-days-five-fun-cranberry-facts/784392002/">contains four air pockets</a>, which is why they float when farmers flood bogs to harvest them. The air pockets also make raw cranberries bounce when they are dropped on a hard surface – a good indicator of whether they are fresh.</p>
<p>These pockets serve a biological role: They enable the berries to float down rivers and streams to disperse their seeds. Many other plants disperse their seeds via animals and birds that eat their fruits and excrete the seeds as they move around. But as anyone who has tasted them raw knows, cranberries are ultra-tart, so they have <a href="https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_viopa2.pdf">limited appeal for wildlife</a>. </p>
<h2>Reading cranberry DNA</h2>
<p>For cranberries being such a young crop, scientists already know <a href="https://doi.org/10.1002/9781119616801.ch8">a lot about their genetics</a>. The cranberry <a href="https://www.genome.gov/genetics-glossary/Diploid">is a diploid</a>, which means that each cell contains one set of chromosomes from the maternal parent and one set from the paternal parent. It has 24 chromosomes, and its genome size is less than one-tenth that of the human genome. </p>
<p>Insights like these help scientists better understand where potentially valuable genes might be located in the cranberry genome. And diploid crops tend to have fewer genes associated with a single trait, which makes breeding them to emphasize that trait much simpler. </p>
<p>Researchers have also described the genetics of the cultivated cranberry’s wild relative, which is known as the “<a href="https://plants.usda.gov/DocumentLibrary/plantguide/pdf/cs_vaox.pdf">small cranberry” (<em>Vaccinium oxycoccos</em>)</a>. Comparing the two can help scientists determine where the cultivated cranberry’s agronomically valuable traits reside in its genome, and where some of the small cranberry’s cold hardiness might come from. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CxGCZq0xv16/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Researchers are <a href="https://www.vacciniumcap.org/">developing molecular markers</a> – tools to determine where certain genes or sequences of interest reside within a genome – to help determine the best combinations of genes from different varieties of cranberry that can enhance desired traits. For example, a breeder might want to make the fruits larger, more firm or redder in color.</p>
<p>While cranberries have only been grown by humans for a short period of time, they have been evolving for much longer. They entered agriculture with a long genetic history, including things like <a href="https://doi.org/10.1371/journal.pone.0264966">whole genome duplication events and genetic bottlenecks</a>, which collectively change which genes are gained or lost over time in a population. </p>
<p>Whole genome duplication events occur when two species’ genomes collide to form a new, larger genome, encompassing all the traits of the two parental species. Genetic bottlenecks occur when a population is greatly reduced in size, which limits the amount of genetic diversity in that species. These events are extremely common in the plant world and can lead to both gains and losses of different genes. </p>
<p>Analyzing the cranberry’s genome can indicate when it diverged evolutionarily from some of its relatives, such as the blueberry, lingonberry and huckleberry. Understanding <a href="https://theconversation.com/modern-tomatoes-are-very-different-from-their-wild-ancestors-and-we-found-missing-links-in-their-evolution-130041">how modern species evolved</a> can teach plant scientists about how different traits are inherited, and how to effectively breed for them in the future.</p>
<h2>Ripe at the right time</h2>
<p>Cranberries’ close association with Thanksgiving was simply a practical matter at first. Fresh cranberries are ready to harvest from mid-September through mid-November, so Thanksgiving falls within that perfect window for eating them. </p>
<p>Cranberry sauce was first loosely described in accounts from the American colonies in the 1600s, and appeared in a <a href="https://www.smithsonianmag.com/history/what-americas-first-cookbook-says-about-our-country-its-cuisine-180967809/">cookbook for the first time in 1796</a>. The berries’ tart flavor, which comes from <a href="https://rucore.libraries.rutgers.edu/rutgers-lib/60677/">high levels of several types of acids</a>, makes them more than twice as acidic as most other edible fruits, so they add a welcome zing to a meal full of blander foods like turkey and potatoes.</p>
<p>In recent decades, the cranberry industry has branched out into <a href="https://theconversation.com/can-cranberries-conquer-the-world-a-us-industry-depends-on-it-87912">juices, snacks and other products</a> in pursuit of year-round markets. But for many people, Thanksgiving is still the time when they’re most likely to see cranberries in some form on the menu.</p><img src="https://counter.theconversation.com/content/216326/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Serina DeSalvio does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Cranberries add color and acidity to Thanksgiving menus, but they also have many interesting botanical and genetic features.Serina DeSalvio, Ph.D. Candidate in Genetics and Genomics, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2168712023-11-06T18:10:14Z2023-11-06T18:10:14ZWildcats lived alongside domestic cats for 2,000 years but only started interbreeding 60 years ago – new study<figure><img src="https://images.theconversation.com/files/557489/original/file-20231103-21-h3kcvd.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4487%2C2980&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are very few wildcats like this one left in their natural habitat in Scotland. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/scottish-wildcat-77377831">Mark Bridger</a></span></figcaption></figure><p>You are unlikely to have seen one, but wildcats are still clinging on by a claw in Scotland. Most of the cats living in the wild in Scotland are hybrid cats with a mix of wildcat and domestic cat ancestry or feral domestic cats. But my team’s new study showed they lived alongside domestic cats for almost 2,000 years before interbreeding. </p>
<p>One of our rarest and most elusive mammal species, European wildcats <a href="https://core.ac.uk/download/pdf/36089455.pdf">have been in decline</a> across across Europe and Britain for the past few hundred years. Wildcats were lost completely from England and Wales by the end of the 19th century and today are <a href="https://www.nms.ac.uk/explore-our-collections/stories/natural-sciences/scottish-wildcat/">only found in the Scottish Highlands</a>.</p>
<p><a href="https://eprints.whiterose.ac.uk/98399/1/38_156_2_PB.pdf">Habitat loss</a> and hunting are two of the biggest threats facing this species across its range, but in Scotland, <a href="https://research-information.bris.ac.uk/ws/portalfiles/portal/355602095/Final_Copy_2022_01_25_Howard_McCombe_J_PhD.pdf">hybridisation with domestic cats</a> is now the biggest threat to this population. Interbreeding between the two species is frequent now. </p>
<p>This gradual erosion of the wildcat genome (<a href="https://www.genome.gov/genetics-glossary/Genome">the DNA instructions</a> for everything that makes a wildcat a wildcat) may lead to the complete extinction of this species in Britain. Among scientists, this is known as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947151/">genetic swamping</a>.</p>
<h2>How long has this been going on?</h2>
<p>Although domestic cats and wildcats are different species, genetically more different than dogs and wolves, they look similar. Domestic cats, <a href="https://www.shh.mpg.de/446464/cat-adna">descended from the African-Asian wildcat</a>, became widespread in Britain in Roman times. </p>
<p>Wildcats in Scotland are a subpopulation of European wildcats, and have been present in Britain <a href="https://savingwildcats.org.uk/about-saving-wildcats/wildcat-conservation-in-scotland/#:%7E:text=Wildcats%20in%20Scotland&text=European%20wildcats%20crossed%20from%20the,brink%20of%20extinction%20in%20Scotland.">since the end of the last ice age</a>, around 10,000 years ago. Our research, which used the genomes of ancient cats from prehistoric Britain (around 6,000BC) until the present, shows that the two species kept themselves separate until very recently. </p>
<p>This may be expected for two species such as these, which have different patterns of behaviour and habitat preference. Wildcats keep away from people and prefer natural, forested areas – unlike domestic cats which thrive in human-modified environments. </p>
<p>My team’s study showed that around 60 years ago, however, there was a sudden shift to increasingly frequent interbreeding, which quickly overwhelmed the remaining wildcats in Scotland.</p>
<h2>What changed?</h2>
<p>The recent history of hybridisation between the two species strongly suggests that hybridisation is a symptom, rather than the cause, of wildcat declines in Britain. </p>
<p>Wildcats have been hunted for sport, and are also <a href="https://news.exeter.ac.uk/faculty-of-humanities-arts-and-social-sciences/managing-domestic-and-wildcats-is-likely-to-remain-fraught-new-research-warns/">persecuted as a pest species</a> which keeps their numbers down. Modern land management has involved the felling of <a href="https://treesforlife.org.uk/into-the-forest/habitats-and-ecology/human-impacts/deforestation/">large swaths of Scottish forests</a> (often for timber or agriculture), potentially forcing wildcats into more human-dominated environments, where they are more likely to meet a domestic cat. </p>
<p>The 20th century also saw a rise in domestic cat ownership, which is now at an all-time high <a href="https://www.cats.org.uk/media/10005/cats-2021-full-report.pdf">in the UK</a>. While it can be hard to keep track of feral domestic cat numbers, the population size is likely to significantly outnumber the wildcat population.</p>
<p>Our study highlighted the pressure that disease transmission is putting on wildcat populations. Domestic cats are a known source of feline diseases, such as <a href="https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-immunodeficiency-virus-fiv">feline immunodeficiency virus</a>, <a href="https://vcahospitals.com/know-your-pet/feline-calicivirus-infection">feline calicivirus</a> and <a href="https://www.langfordvets.co.uk/media/1748/feline-haemoplasma.pdf">haemoplasma infection</a>, which can be passed to wildcats, and can be deadly.</p>
<figure class="align-center ">
<img alt="Wildcat kittens play on the forest floor." src="https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557490/original/file-20231103-25-a24sfc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wildcats look similar to domestic cats.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/wild-cat-kittens-fighting-406815661">Libor Fousek/Shutterstock</a></span>
</figcaption>
</figure>
<p>Our study compared the genomes of hybrid, wildcat and domestic cats. The hybrid population showed genetic patterns suggesting they are developing immunity to these diseases, with the help of genes inherited from domestic cat parents. While this may bring short-term protection from cat diseases, it results in domestic cat DNA hitching along for the ride, perhaps accelerating the effect of genetic swamping. </p>
<p>Without intervention, the few wildcats that remain will interbreed with domestic cats and the wildcat genome will contribute a fraction of a percent to the domestic cat genome. The biological and behavioural adaptations that evolved in the European wildcat will be lost.</p>
<h2>Does this matter?</h2>
<p>Human behaviour (such as transporting species around the world, encroachment on wild habitats and climate change) is driving an increase in hybridisation globally. Conservationists are debating the level of risk this poses to wildlife populations, and the best course of action for conservation management.</p>
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<strong>
Read more:
<a href="https://theconversation.com/hybrid-future-interbreeding-can-make-heat-averse-species-more-resilient-to-climate-change-198877">Hybrid future? Interbreeding can make heat-averse species more resilient to climate change</a>
</strong>
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<p>In some cases hybridisation can be beneficial, bringing new genetic diversity that can help species survive in increasingly human-dominated environments. However, the consequences of hybridisation are unpredictable, and it is hard to come up with a solution that works for every case. </p>
<p>For the wildcat, hybridisation is a double-edged sword. It brought disease resistance that aided the population’s short-term survival, but at the cost of threatening the genetic adaptations that made the species unique.</p>
<h2>What next for wildcats?</h2>
<p>My team’s study highlights the value of the <a href="https://www.rewildingbritain.org.uk/reintroductions-key-species/key-species/wildcat">captive wildcat population</a> in the UK. First established in 1960, founders of this population largely predate the onset of hybridisation in Scotland. The captive population now provides an important lifeline to reestablish this species in Britain. </p>
<p>A wildcat conservation breeding for release programme is conducted by <a href="https://savingwildcats.org.uk/">Saving Wildcats</a>, a partnership led by the Royal Zoological Society of Scotland. The first releases into the wild started this year, with 19 cats released in the Cairngorms Connect area of the Cairngorms National Park. </p>
<p>Monitoring the newly released cats will give us vital insights about how to protect species like the wildcat. The more we understand about the effects and history of hybridisation, the more we’ll understand about how best to manage wildlife conservation in the future. </p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/216871/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joanna Howard-McCombe received funding from NERC, the RZSS and the People's Trust for Endangered Species. </span></em></p><p class="fine-print"><em><span>Mark Beaumont received funding from NERC. </span></em></p><p class="fine-print"><em><span>Daniel J. Lawson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>And a recent history of wildcat hybridisation.Jo Howard-McCombe, Research scientist, University of BristolDaniel J. Lawson, Associate Professor in Data Science, University of BristolMark Beaumont, Professor of Statistics, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2156982023-11-01T12:35:53Z2023-11-01T12:35:53ZCancer has many faces − 5 counterintuitive ways scientists are approaching cancer research to improve treatment and prevention<figure><img src="https://images.theconversation.com/files/553918/original/file-20231016-15-3osk1.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2700%2C1758&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cancer cells don't follow the typical rules that allow a multicellular collective to function.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cancer_cells_(1).jpg">Dr. Cecil Fox/National Cancer Institute</a></span></figcaption></figure><p>How researchers conceptualize a disease informs how they treat it. Cancer is often described as uncontrollable cell growth triggered by genetic damage. But cancer can also be seen from angles that emphasize mathematics, evolutionary game theory and physics, among others.</p>
<p>Molecular biology has brought significant advances in making it possible to live with cancer as a chronic illness rather than a fatal disease. Alternative frameworks, however, can offer scientists additional insights on how to prevent tumors from spreading throughout the body and becoming resistant to treatment.</p>
<p>Here are a few unconventional lenses through which researchers are viewing cancer with fresh eyes, drawn from The Conversation’s archives.</p>
<h2>1. Evolution and natural selection of cancer</h2>
<p>The body is far from a wonderland for cells. Each individual cell competes against trillions of others for finite space and nutrients. If they’re able to cooperate in an orderly enough fashion, sharing resources and dividing labor, the collective functions effectively. Cancer cells, however, <a href="https://theconversation.com/microbes-in-your-food-can-help-or-hinder-your-bodys-defenses-against-cancer-how-diet-influences-the-conflict-between-cell-cooperators-and-cheaters-195810">cheat the system</a>: They hog resources, take up as much space as possible and <a href="https://theconversation.com/what-are-hela-cells-a-cancer-biologist-explains-169913">refuse to die</a>.</p>
<p>In this way, cancer can be thought of as <a href="https://theconversation.com/every-cancer-is-unique-why-different-cancers-require-different-treatments-and-how-evolution-drives-drug-resistance-199249">an evolutionary disease</a> – these are cells that have developed the genetic mutations to outcompete their neighbors, and subsequent cell generations inherit this survival advantage. Cancer cells benefit at the expense of the collective until the entire organism collapses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of pancreas tumor with multicolored cell subgroups" src="https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=458&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=458&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=458&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=575&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=575&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554078/original/file-20231016-27-4u7mpn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=575&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Most tumors are made of many different kinds of cancer cells, as shown in this pancreatic cancer sample from a mouse.</span>
<span class="attribution"><a class="source" href="https://visualsonline.cancer.gov/details.cfm?imageid=10654">Ravikanth Maddipati/Abramson Cancer Center at the University of Pennsylvania via National Cancer Institute</a></span>
</figcaption>
</figure>
<p>Oncologist <a href="https://cancer.psu.edu/researchers/individual/-/researcher/5B6500F63D6A38DBE0540010E056499A/monika-joshi-md-mrcp">Monika Joshi</a> and pathologists <a href="https://cancer.psu.edu/researchers/individual/-/researcher/5F6E820FF5C14A2DE0540010E056499A/joshua-warrick-md">Joshua Warrick</a> and <a href="https://scholar.google.com/citations?user=YEqQHkIAAAAJ&hl=en">David DeGraff</a> believe that understanding evolution is key to understanding cancer. Screening programs are effective, for example, because removing a nascent tumor is easier than treating one that has evolved the ability to spread. Cancer cells likewise become resistant to treatments because they’re pushed to further evolve to survive.</p>
<p>Some researchers are applying the principles of evolutionary game theory to <a href="https://theconversation.com/cancers-are-in-an-evolutionary-battle-with-treatments-evolutionary-game-theory-could-tip-the-advantage-to-medicine-17017">reduce treatment resistance</a> and optimize <a href="https://theconversation.com/cancer-in-kids-is-different-from-cancer-in-grown-ups-figuring-out-how-could-lead-to-better-pediatric-treatments-212738">therapies for children</a>.</p>
<p>“The fight against cancer is a fight against evolution, the fundamental process that has driven life on Earth since time immemorial,” they wrote. “This is not an easy fight, but medicine has made tremendous progress.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/every-cancer-is-unique-why-different-cancers-require-different-treatments-and-how-evolution-drives-drug-resistance-199249">Every cancer is unique – why different cancers require different treatments, and how evolution drives drug resistance</a>
</strong>
</em>
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<h2>2. Fluid mechanics of cancer</h2>
<p>As much as cancer is a disease that respects no boundaries, tumor cells are still shaped by their environment. Unlike healthy cells that take the hint when their presence isn’t wanted, however, tumor cells not only <a href="https://theconversation.com/stopping-the-cancer-cells-that-thrive-on-chemotherapy-research-into-how-pancreatic-tumors-adapt-to-stress-could-lead-to-a-new-treatment-approach-197768">survive but thrive in stressful conditions</a>. Isolated cancer cells able to adapt to harsh settings are the ones that establish metastatic colonies and become resistant to treatment.</p>
<p>While researchers have focused on how biochemical signals direct cells to move from one location to another, a cell’s physical environment also affects where it migrates. Mechanical engineer <a href="https://scholar.google.com/citations?user=nKmJNpQAAAAJ&hl=en">Yizeng Li</a> found that a cell’s “solid” and “fluid” surroundings influence its movement.</p>
<p>Cancer cells encounter varying degrees of fluid viscosity, or thickness, as they travel through the body. Li and her team found that breast cancer cells counterintuitively move faster in high viscosity environments by changing their structure. This meant that fluid viscosity serves as a <a href="https://theconversation.com/how-cancer-cells-move-and-metastasize-is-influenced-by-the-fluids-surrounding-them-understanding-how-tumors-migrate-can-help-stop-their-spread-195792">mechanobiological cue for cancer cells to metastasize</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Animation comparing two fluids with lower and higher viscosity." src="https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502975/original/file-20230103-105030-c8xq8d.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The blue fluid on the left has a lower viscosity relative to the orange fluid on the right.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Viscosities.gif">Synapticrelay/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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</figure>
<p>“Cancer patients usually don’t die from the original source of the tumor but from its spread to other parts of the body,” Li wrote. “Understanding how fluid viscosity affects the movement of tumor cells could help researchers figure out ways to better treat and detect cancer before it metastasizes.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-cancer-cells-move-and-metastasize-is-influenced-by-the-fluids-surrounding-them-understanding-how-tumors-migrate-can-help-stop-their-spread-195792">How cancer cells move and metastasize is influenced by the fluids surrounding them – understanding how tumors migrate can help stop their spread</a>
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<hr>
<h2>3. Inflammation link to cardiovascular disease</h2>
<p>Apart from being leading causes of death around the world, cardiovascular disease and cancer may not initially seem to have much in common. The many risk factors they share, however – like poor diet, smoking and chronic stress – coalesce with chronic inflammation: persistent, low-grade activation of the immune system can damage cells in ways that encourage either disease to develop. </p>
<p>For biomedical engineer <a href="https://scholar.google.com/citations?user=wD6KbXkAAAAJ&hl=en">Bryan Smith</a>, the developmental parallels between these diseases signal they could be <a href="https://theconversation.com/could-a-single-drug-treat-the-two-leading-causes-of-death-in-the-us-cancer-and-cardiovascular-disease-205461">treated at the same time</a>.</p>
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<figcaption><span class="caption">Nanoparticles can ‘eat’ the plaques that cause heart disease.</span></figcaption>
</figure>
<p><a href="https://theconversation.com/drugs-4-essential-reads-on-how-theyre-made-how-they-work-and-how-context-can-make-poison-a-medicine-192590">Drugs can be repurposed</a> to target diseases for which they weren’t originally designed. Certain drugs, for example, can direct immune cells called macrophages to consume both cancer cells and the cellular debris that contribute to cardiovascular plaques.</p>
<p>“As basic science discovers other molecular parallels between these diseases, patients will be the beneficiaries of better therapies that can treat both,” wrote Smith.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/could-a-single-drug-treat-the-two-leading-causes-of-death-in-the-us-cancer-and-cardiovascular-disease-205461">Could a single drug treat the two leading causes of death in the US: cancer and cardiovascular disease?</a>
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<hr>
<h2>4. Mathematics of cancer</h2>
<p>In certain contexts, math has unique strengths in <a href="https://theconversation.com/big-bang-of-numbers-the-conversations-book-club-explores-how-math-alone-could-create-the-universe-with-author-manil-suri-213690">describing the natural world</a>. For instance, epigenetics – where and when genes are turned on or off – plays as much a role in cancer progression as direct changes to the genetic code. Epigenetic changes can alter healthy cells to the point of losing their normal form and function. But the randomness of these changes makes it difficult to tease out pathological from normal genetic activity.</p>
<p>A mathematical concept called stochasticity – or how the randomness of the steps of a process influences how predictable its outcome will be – lends a logical framework to the <a href="https://theconversation.com/cancer-evolution-is-mathematical-how-random-processes-and-epigenetics-can-explain-why-tumor-cells-shape-shift-metastasize-and-resist-treatments-199398">epigenetic changes contributing to cancer</a>, clarifying when healthy cells rapidly develop into tumor cells. </p>
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<figcaption><span class="caption">Twins sharing the exact same genome can develop in completely different ways because of epigenetics.</span></figcaption>
</figure>
<p>Stochasticity is commonly used to study stock market behavior and epidemic disease spread, and researchers quantify it by examining the degree of uncertainty, or entropy, of a particular outcome. Identifying high entropy areas in the genome could offer another approach to cancer detection and drug design.</p>
<p>Cancer geneticist <a href="https://scholar.google.com/citations?user=tbj-LpcAAAAJ&hl=en">Andrew Feinberg</a> has been using entropy to quantitatively describe the epigenetics of cancer. He and his colleagues found that high entropy regions of the genome in the skin become even more entropic with sun damage, increasing the chance of developing cancer. This offers a potential explanation for why cancer risk significantly increases with age.</p>
<p>“Epigenetic entropy shows that you can’t fully understand cancer without mathematics,” Feinberg wrote. “Biology is catching up with other hard sciences in incorporating mathematical methods with biological experimentation.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cancer-evolution-is-mathematical-how-random-processes-and-epigenetics-can-explain-why-tumor-cells-shape-shift-metastasize-and-resist-treatments-199398">Cancer evolution is mathematical – how random processes and epigenetics can explain why tumor cells shape-shift, metastasize and resist treatments</a>
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<h2>5. A public health issue</h2>
<p>Cancer is a disease that develops in an individual, but its socially derived causes and societal-wide effects are hardly limited to a single person.</p>
<p>Take the case of lung cancer. It is stigmatized as a disease brought on by poor lifestyle choices – a consequence of a personal decision to use tobacco products. But as thoracic oncologist <a href="https://doctors.umiamihealth.org/provider/Estelamari+Rodriguez/1257821">Estelamari Rodriguez</a> noted, the face of lung cancer has changed.</p>
<p>“Over the past 15 years, more women, never-smokers and younger people are being diagnosed with lung cancer,” she wrote. While lung cancer rates have significantly decreased for men, they have <a href="https://theconversation.com/lung-cancer-rates-have-decreased-for-the-marlboro-man-but-have-risen-steeply-for-nonsmokers-and-young-women-an-oncologist-explains-why-197581">substantially risen for women</a> around the world. Despite being the leading cause of cancer death among women, screening rates remain low compared with other cancers.</p>
<p>More broadly, cancer symptoms are often unrecognized or misdiagnosed, not only <a href="https://theconversation.com/ovarian-cancer-is-not-a-silent-killer-recognizing-its-symptoms-could-help-reduce-misdiagnosis-and-late-detection-181415">for women</a> but also for many marginalized populations, including <a href="https://theconversation.com/biopsies-confirm-a-breast-cancer-diagnosis-after-an-abnormal-mammogram-but-structural-racism-may-lead-to-lengthy-delays-185824">people of color</a>, <a href="https://theconversation.com/doctors-often-arent-trained-on-the-preventive-health-care-needs-of-gender-diverse-people-as-a-result-many-patients-dont-get-the-care-they-need-191933">transgender patients</a> and <a href="https://theconversation.com/how-obamacare-has-helped-poor-cancer-patients-85306">the uninsured</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/yRDDMX8vFrg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An increasing number of lung cancer diagnoses are among people who never smoked.</span></figcaption>
</figure>
<p>These disparities are due in part to biases in medical education and <a href="https://theconversation.com/yes-black-patients-do-want-to-help-with-medical-research-here-are-ways-to-overcome-the-barriers-that-keep-clinical-trials-from-recruiting-diverse-populations-185337">clinical research</a> that fail to prepare clinicians to care for the diversity of patients they’ll encounter. <a href="https://theconversation.com/the-next-attack-on-the-affordable-care-act-may-cost-you-free-preventive-health-care-166087">Tenuous access to preventive care</a> and disproportionate <a href="https://theconversation.com/arsenic-contamination-of-food-and-water-is-a-global-public-health-concern-researchers-are-studying-how-it-causes-cancer-200689">exposure to carcinogens</a> among certain populations compound these inequities.</p>
<p>The purview of cancer goes far beyond a single discipline. It takes a village of researchers, policymakers and patient advocates to achieve effective and accessible cancer care for all.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lung-cancer-rates-have-decreased-for-the-marlboro-man-but-have-risen-steeply-for-nonsmokers-and-young-women-an-oncologist-explains-why-197581">Lung cancer rates have decreased for the Marlboro Man, but have risen steeply for nonsmokers and young women – an oncologist explains why</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/215698/count.gif" alt="The Conversation" width="1" height="1" />
From math to evolutionary game theory, looking at cancer through different lenses can offer further insights on how to approach treatment resistance, metastasis and health disparities.Vivian Lam, Associate Health and Biomedicine EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1936152023-10-22T11:41:39Z2023-10-22T11:41:39ZThe 23andMe data breach reveals the vulnerabilities of our interconnected data<figure><img src="https://images.theconversation.com/files/554853/original/file-20231019-20-wrblg3.jpg?ixlib=rb-1.1.0&rect=13%2C0%2C3040%2C1964&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Users' genetic information was accessed during a hacker attack on the 23andMe's user databases.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>On Oct. 6, news broke that 23andMe, the genomics company that collects genetic material from thousands of people for ancestry and genetic predisposition tests, <a href="https://www.wired.com/story/23andme-credential-stuffing-data-stolen/">had a massive data breach</a>. </p>
<p>But as it turns out, the company’s servers were not hacked. Rather, hackers targeted hundreds of individual user accounts — allegedly those that had <a href="https://blog.23andme.com/articles/addressing-data-security-concerns">repeated passwords</a>. After gaining access to the accounts, hackers could leverage the “<a href="https://customercare.23andme.com/hc/en-us/articles/115004659068-DNA-Relatives-The-Genetic-Relative-Basics">DNA relatives matches</a>” function of 23andMe to get information about thousands of other people.</p>
<p>This data breach challenges how we think about privacy, data security and corporate accountability in the information economy.</p>
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<figcaption><span class="caption">Hackers targeted user passwords to access 23andMe’s user data.</span></figcaption>
</figure>
<h2>Shared information</h2>
<p>Genetic information databases have a notable feature: anyone’s DNA data also reveals information about others who share part of their genetic code with them. When someone sends a sample to 23andMe, the company has genetic information about that person <em>and</em> their relatives even if those relatives didn’t send a sample or consent to any data collection. Their data is inevitably intertwined.</p>
<p>This isn’t just a characteristic of genetic data. Most data is about more than one person because data often describes shared features between people.</p>
<p>The ramifications of overlooking how personal data affects others <a href="https://www.forbes.com/advisor/business/what-is-data-breach/">extend to the entire information economy</a>. Every individual choice about personal data has spillover effects on others. People are exposed to consequences — ranging from financial loss to discrimination — stemming from data practices that depend not only on information about themselves, but also on information about others. </p>
<p>User data-collection agreements can lead to indirect harm to third parties. For example, the negative impacts of the <a href="https://www.nytimes.com/2018/04/04/us/politics/cambridge-analytica-scandal-fallout.html">Cambridge Analytica scandal extended</a> far beyond those whose data the company collected.</p>
<p>This predicament underscores the collective impact of individual data decisions. </p>
<h2>Data analytics</h2>
<p>Algorithms powered by artificial intelligence draw inferences by analyzing the relationships between data points. AI algorithms rely on databases containing information about multiple people to learn things about a particular person or a particular group. </p>
<p>Companies draw conclusions about people by analyzing data collected from others, making probabilistic assessments based on personal characteristics and relationships. Companies continue to add information about people to their datasets daily. And, the more people a dataset like the one built by 23andMe includes, the less someone’s choice not to be part of it matters.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a thumb presses a heart button on a smartphone screen" src="https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554855/original/file-20231019-18-a4ar1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">AI-powered algorithms analyze user information and the connections and relationships with other people’s data.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Similarly, every time a user agrees to the collection, processing or sharing of personal information, it also affects others who share similarities with the user. These collective assessments make data processing profitable, such as through marketing, data sales and business decisions based on consumer behaviour. </p>
<h2>Equity issues</h2>
<p>The interconnected nature of data isn’t a coincidence — it’s at the core of how businesses operate in the information economy. This also creates equity issues.</p>
<p>In the 23andMe case, hackers are offering the assembled genetic information for sale, <a href="https://www.reuters.com/technology/hackers-advertise-sale-23andme-data-leaked-data-forum-2023-10-06/">with lists that include thousands of people</a>. Hackers reportedly assembled and put up for sale <a href="https://nationalpost.com/news/hacker-puts-millions-of-23andme-user-data-up-for-sale-on-the-internet">lists of people with Ashkenazi Jewish ancestry</a>. </p>
<p>Individuals on the list now face increased risk of discrimination or harassment, as leaked data includes names and location. Other information from the company would allow them to do the same for people with a propensity for Type 2 diabetes, Parkinson’s disease or dementia — all of which 23andMe measures — putting them at risk of other harms, from raised insurance premiums to employment discrimination. </p>
<h2>Data’s collective risks</h2>
<p>We often fail to acknowledge the interconnected nature of data because we’re fixated on each individual. As a consequence, companies can exploit one person’s agreement to legitimize data practices involving others. Companies’ legal obligations to obtain individual agreements for data collection fail to recognize broader interests beyond those of the person who agreed. </p>
<p>We need privacy laws attuned to how the information economy works. Providing consent on behalf of others, as 23andMe users did when they clicked “I agree,” would be illegitimate under any meaningful notion of consent. To contain group data harms like those this hack produced, we need substantive rules about what companies can and can’t do. </p>
<p>Prohibitions on indiscriminate data collection and risky data uses avoid leaving unsuspecting individuals as collateral damage. Because corporate data practices can impact <em>everyone</em>, their safety obligations should too.</p>
<p><em>This is a corrected version of a story originally published on Oct. 22, 2023. The earlier story incorrectly said that 23andMe was owned by Google, the data breach was as a result of weak rather than repeated passwords, and affected the public, rather than users of 23andMe’s services who opted into the “DNA relatives matches” feature.</em></p><img src="https://counter.theconversation.com/content/193615/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ignacio Cofone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Our online data is inevitably intertwined with the data of others. Current protections are ill-equipped to address this reality and manage the far-ranging impacts of data breaches.Ignacio Cofone, Associate professor, Law, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2059142023-09-15T12:36:15Z2023-09-15T12:36:15ZAlzheimer’s disease is partly genetic − studying the genes that delay decline in some may lead to treatments for all<figure><img src="https://images.theconversation.com/files/548111/original/file-20230913-29-y9h0zu.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5483%2C4108&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers are zeroing in on understanding what goes awry in the brains of people with Alzheimer's disease.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/alzheimers-and-dementia-research-conceptual-image-royalty-free-image/1414387544?phrase=alzheimer%27s+disease&adppopup=true">Tek Image/Science Photo Library via Getty Images</a></span></figcaption></figure><p>Diseases that run in families usually have genetic causes. Some are <a href="https://www.genome.gov/For-Patients-and-Families/Genetic-Disorders">genetic mutations</a> that directly cause the disease if inherited. Others are <a href="https://theconversation.com/explainer-what-is-genetic-risk-25969">risk genes</a> that affect the body in a way that increases the chance someone will develop the disease. In <a href="https://www.nia.nih.gov/health/alzheimers-disease-genetics-fact-sheet">Alzheimer’s disease</a>, genetic mutations in any of three specific genes can cause the disease, and other risk genes either increase or decrease the risk of developing Alzheimer’s. </p>
<p>Some genetic mutations or variants interact with other genetic alterations that lead to Alzheimer’s disease. In some cases, gene alterations can interact with Alzheimer’s-causing genetic variants in a way that proves beneficial; they actually suppress the pathological brain changes the other mutations would normally lead to. These protective gene variants can drastically slow or prevent cognitive decline. In <a href="https://doi.org/10.1038/s41591-019-0611-3">two recent</a> <a href="https://doi.org/10.1038/s41591-023-02318-3">case reports</a> on familial Alzheimer’s disease, mutations delayed Alzheimer’s symptoms for decades.</p>
<p>I am a <a href="https://scholar.google.com/citations?user=Jbl0lnsAAAAJ&hl=en">neurologist and neuroscientist</a> who has spent my career studying Alzheimer’s disease and dementia both in the laboratory and in the clinic. Determining how genes affect brain chemistry is vital to understanding how Alzheimer’s disease progresses and devising interventions to prevent or delay cognitive decline.</p>
<h2>The amyloid hypothesis</h2>
<p>In the early 1990s, scientists proposed the <a href="https://doi.org/10.1111/j.1750-3639.1991.tb00667.x">amyloid hypothesis</a> to explain how Alzheimer’s disease develops. The first neuropathological changes detected in the brain of Alzheimer’s disease patients were the formation of <a href="https://doi.org/10.1016/0165-6147(91)90609-v">amyloid plaques</a> – clumps of protein pieces called beta-amyloid. Other changes in the Alzheimer’s brain, such as the accumulation of another type of abnormal protein called neurofibrillary tangles, were thought to develop later in the course of the disease.</p>
<p>Beta-amyloid begins to accumulate in the brain <a href="https://doi.org/10.1038/s41582-018-0116-6">up to 15 years</a> before symptoms emerge. Symptoms correlate with the <a href="https://doi.org/10.1007%2Fs00401-019-02036-6">number of neurofibrillary tangles</a> in the brain – the more tangles, the worse the cognition. Researchers have tried to determine whether preventing or removing amyloid plaques from the brain would be an effective treatment. </p>
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<figcaption><span class="caption">Alzheimer’s disease results from the accumulation of abnormal proteins in the brain.</span></figcaption>
</figure>
<p>Imagine the excitement of the scientific community in the 1990s when researchers identified three different genes causing familial Alzheimer’s disease – and all three were involved with beta-amyloid.</p>
<p>The first was the <a href="https://doi.org/10.1038/349704a0">amyloid precursor protein</a> gene. This gene directs cells to produce the amyloid precursor protein, which breaks down into smaller fragments, including the beta-amyloid that forms amyloid plaques in the brain.</p>
<p>The second gene was termed <a href="https://doi.org/10.1038/349704a0">presenilin 1, or PSEN-1</a>, a protein needed to cut the precursor protein into beta-amyloid. </p>
<p>The third gene, <a href="https://doi.org/10.1038/376775a0">presenilin 2, or PSEN-2</a>, is closely related to PSEN-1 but found in a smaller number of families with familial Alzheimer’s disease.</p>
<p>These findings added strength to the amyloid hypothesis explanation of the disease. However, <a href="https://doi.org/10.15252/emmm.201606210">uncertainty and opposition to the amyloid hypothesis</a> have developed over the past several decades. This was in part tied to a recognition that several other processes – neurofibrillary tangles, inflammation and immune system activation – are also involved in the neurodegeneration seen in Alzheimer’s. </p>
<p><a href="http://dx.doi.org/10.2174/1570159X15666170116143743">The hypothesis also</a> <a href="https://mitpress.mit.edu/9780262546010/how-not-to-study-a-disease/">got significant pushback</a> after <a href="https://doi.org/10.14283/jpad.2019.23">many clinical trials</a> attempting to block the effects of amyloid or remove it from the brain <a href="https://www.theatlantic.com/health/archive/2017/02/alzheimers-amyloid-hypothesis/517185/">were unsuccessful</a>. In some cases, treatments had significant side effects. Some researchers have <a href="https://doi.org/10.15252/emmm.201606210">come up with strong defenses</a> of the hypothesis. But until a clinical trial based on the amyloid hypothesis could show definitive results, uncertainty would remain. </p>
<h2>Genetic discoveries with treatment implications</h2>
<p>The vast majority – <a href="https://doi.org/10.1016/j.jalz.2016.01.012">more than 90%</a> – of Alzheimer’s cases occur in late life, with disease prevalence increasing progressively from age 65 and up. Such cases are mostly sporadic, with no clear family history of Alzheimer’s.</p>
<p>However, a relatively small number of families have one of the three known genetic mutations that cause the disease to be passed down. In <a href="http://dx.doi.org/10.1016/j.jalz.2016.01.012">familial Alzheimer’s</a>, 50% of each generation will inherit the mutated gene and develop the disease much earlier, usually from their 30s to early 50s.</p>
<p>In 2019 and 2023, researchers identified changes in at least two other genes that markedly delayed the onset of disease symptoms in people with familial Alzheimer’s disease mutations. These mutated genes were found in a very large family in Colombia whose members tended to develop Alzheimer’s symptoms by their 40s.</p>
<p>A <a href="https://doi.org/10.1038/s41591-019-0611-3">woman in the family</a> carrying a mutated PSEN-1 gene <a href="https://www.sciencenews.org/article/colombia-family-genetic-mutation-alzheimers-dementia-treatment">did not have any cognitive symptoms</a> until she was in her 70s. A genetic analysis showed that she had an additional mutation in a variant of the gene that codes for a <a href="https://doi.org/10.1126/science.aba0964">protein called apolipoprotein E</a>, or ApoE. Researchers believe the mutation, called the <a href="https://www.alz.org/news/2022/unlocking-the-christchurch-variant">Christchurch variant</a> – named after the city in New Zealand where the mutation was first discovered – is responsible for interfering with and slowing down her disease. </p>
<p>Importantly, her brain had a great deal of amyloid plaque but very few neurofibrillary tangles. This suggests that the link between the two was broken and that the suppressed number of neurofibrillary tangles also slowed down cognitive loss.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/WWMzfKeUeYg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Researchers have studied certain families in Colombia with rare genetic variants that slow the progression of Alzheimer’s disease.</span></figcaption>
</figure>
<p>In May 2023, researchers reported that <a href="https://doi.org/10.1038/s41591-023-02318-3">two siblings in the same large family</a> also did not develop memory problems until their 60s or late 70s and were found to carry a mutation in a gene that codes for a protein called reelin. Studies in mice suggest that reelin has <a href="https://doi.org/10.1038/ncomms4443">protective effects against amyloid plaque deposition</a> in the brain. In these patients’ brains, as with the patient who had the Christchurch variant, there were extensive amyloid plaques but very few neurofibrillary tangles. This observation confirmed that the tangles are responsible for the cognitive loss and that there are several ways to “disconnect” amyloid and neurofibrillary tangle accumulation.</p>
<p>Finding medicines that might mimic the protective effects of the Christchurch variant or the reelin mutation could help delay Alzheimer’s disease symptoms for all patients. Since the vast majority of nonfamilial Alzheimer’s manifests after age 70 or 75, a 10-year delay in the emergence of first symptoms of Alzheimer’s could have a massive effect in <a href="https://doi.org/10.1016/s1474-4422(14)70136-x">decreasing the prevalence of the disease</a>.</p>
<p>These findings demonstrate that Alzheimer’s can be slowed and will hopefully lead to additional new therapies that can someday not only treat the disease but prevent it as well.</p>
<h2>Starts and stops</h2>
<p>Despite over 20 years of doubts and therapy failures, the past several years have seen positive results from three different treatments – aducanumab, lecanemab and donanemab – that remove amyloid plaques and slow loss of cognitive function to some extent. Although there is still discussion of how much slowing of decline is clinically significant, these successes provide support for the amyloid hypothesis. They also suggest that other strategies will be needed for optimal treatment.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sy82KB9T3ZY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The FDA approved the Alzheimer’s drug aducanumab (Aduhelm) in June 2021, to much controversy.</span></figcaption>
</figure>
<p>The U.S. Food and Drug Administration’s 2021 approval of the first antibody treatment for Alzheimer’s, <a href="https://theconversation.com/the-fdas-big-gamble-on-the-new-alzheimers-drug-162396">aducanumab, sold under the brand name Aduhelm</a>, was controversial. Only one of the two clinical trials testing its safety and effectiveness in people yielded positive results. The FDA approved the drug on the basis of that single study through an <a href="https://theconversation.com/the-fda-approved-a-new-drug-to-treat-alzheimers-but-medicare-wont-always-pay-for-it-a-doctor-explains-what-researchers-know-about-biogens-aduhelm-179177">accelerated approval process</a> in which treatments meeting an unmet clinical need can receive expedited approval.</p>
<p>The second antibody, <a href="https://theconversation.com/what-the-fdas-accelerated-approval-of-a-new-alzheimers-drug-could-mean-for-those-with-the-disease-5-questions-answered-about-lecanemab-197460">lecanemab, sold as Leqembi</a>, was approved in January 2023 via the same accelerated approval pathway. It was then <a href="https://www.fda.gov/news-events/press-announcements/fda-converts-novel-alzheimers-disease-treatment-traditional-approval">fully approved</a> in July 2023.</p>
<p>The third antibody, donanemab, completed a successful <a href="https://doi.org/10.1001/jama.2023.13239">phase three clinical trial</a> and is awaiting more safety data. When that is submitted to the FDA, the agency will consider the drug for approval.</p><img src="https://counter.theconversation.com/content/205914/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven T. DeKosky consults for Brainstorm Cell Therapeutics and Novo Nordisk Pharmaceuticals; is the Editor for Dementia for Up-To-Date, a point of care electronic textbook of medicine and is Associate Editor of Neurotherapeutics-The Journal of the American Society for Experimental Therapeutics (ASENT); chairs Drug Monitoring Safety Boards for Biogen, Prevail Pharmaceuticals, and Vaccinex Pharmaceuticals; and chairs Scientific Advisory Boards for Acumen Pharmaceuticals and Cognition Therapeutics.</span></em></p>Despite decades of starts and stops, new treatments and key genetic discoveries are giving researchers great hope for slowing or eventually preventing Alzheimer’s disease.Steven DeKosky, Professor of Neurology and Neuroscience, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2093122023-09-15T12:31:41Z2023-09-15T12:31:41ZCan at-home DNA tests predict how you’ll respond to your medications? Pharmacists explain the risks and benefits of pharmacogenetic testing<figure><img src="https://images.theconversation.com/files/545852/original/file-20230831-15-xftd5k.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2070%2C1449&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pharmacogenetic testing is a form of precision medicine, using your genes to personalize your care.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/medicine-concept-royalty-free-image/815702424">D3Damon/E+ via Getty Images</a></span></figcaption></figure><p>Have you ever wondered why certain medications <a href="https://theconversation.com/why-prescription-drugs-can-work-differently-for-different-people-168645">don’t seem to work as well</a> for you as they do for others? This variability in drug response is what pharmacogenomic testing hopes to explain by looking at the genes within your DNA. </p>
<p><a href="https://www.cdc.gov/genomics/disease/pharma.htm">Pharmacogenomics, or PGx</a>, is the study of how genes affect your response to medications. <a href="https://www.genome.gov/genetics-glossary/Gene">Genes are segments of DNA</a> that serve as an instruction manual for cells to make proteins. Some of these proteins break down or transport certain medications through the body. Others are proteins that medications target to generate a desired effect.</p>
<p><a href="https://www.pharmacy.pitt.edu/people/kayla-rowe">As pharmacists</a> <a href="https://scholar.google.com/citations?user=9Np7_DYAAAAJ&hl=en">who see</a> <a href="https://scholar.google.com/citations?user=LKG31OkAAAAJ&hl=en">patients who</a> have stopped multiple medications because of side effects or ineffectiveness, we believe pharmacogenomic testing has the potential to help guide health care professionals to more precise dosing and prescribing.</p>
<h2>How do PGx tests work?</h2>
<p><a href="https://medlineplus.gov/lab-tests/pharmacogenetic-tests/">PGx tests</a> look for variations within the genes of your DNA to predict drug response. For instance, the presence of one genetic variant might predict that the specific protein it codes for is unable to break down a particular medication. This could potentially lead to increased drug levels in your body and an increased risk of side effects. The presence of another genetic variant might predict the opposite: It might predict that the protein it codes for is breaking down a medication more rapidly than expected, which may decrease the drug’s effectiveness.</p>
<p>For example, <a href="https://doi.org/10.1002/cpt.2903">citalopram is an antidepressant</a> broken down by a protein called CYP2C19. Patients with genetic variants that code for a version of this protein with a reduced ability to break down the drug may have an increased risk of side effects.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/dGMIyzCRl-A?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">PGx is a form of personalized or precision medicine.</span></figcaption>
</figure>
<p>Currently, there are over 80 medications with <a href="https://cpicpgx.org/">prescribing recommendations</a> based on PGx results, including treatments for depression, cancer and heart disease. There are commercially available PGx tests that patients can have sent directly to their doorstep with or without the involvement of a health care professional. These direct-to-consumer PGx tests collect DNA from either a saliva sample or cheek swab that is then sent to the laboratory. Results can take anywhere from a few days to a few weeks depending on the company. </p>
<p>Some companies <a href="https://doi.org/10.1038%2Fnature15817">require a consultation</a> with a health care provider, often a pharmacist or genetic counselor, who can facilitate a test order and discuss any medication changes once the results come back. </p>
<h2>Limitations of PGx testing</h2>
<p>PGx testing will not be able to predict how you will respond to all medications for several reasons.</p>
<p>First, most PGx tests <a href="https://doi.org/10.3390/genes11121456">do not look for every possible variant</a> of every gene in the human genome. Instead, they look only at a limited number of genes and variants strongly linked to specific drugs. PGx tests can predict how you will respond only to medications associated with the genes it tests for. </p>
<p>Some drugs are broken down in very complicated pathways entailing multiple proteins and byproducts, and the usefulness of PGx testing for them remains unclear. For example, the <a href="https://www.pharmgkb.org/pathway/PA166170276">antidepressant bupropion</a> has three major pathways involved in its breakdown and forms three active byproducts that can interact with other drugs or body processes. This makes predicting how you will respond to the drug much more challenging because there is more than one variable involved. In many cases, there also isn’t conclusive data to confidently predict the general function of a protein and how it would affect your response to a drug.</p>
<p>The applicability of PGx test results is additionally limited by a <a href="https://theconversation.com/uncovering-the-genetic-basis-of-mental-illness-requires-data-and-tools-that-arent-just-based-on-white-people-this-international-team-is-collecting-dna-samples-around-the-globe-185997">lack of diversity of study participants</a>. Typically, populations of European ancestry are overrepresented in clinical trials. An ongoing research initiative by the National Institutes of Health called the <a href="https://allofus.nih.gov/">All of Us Research Program</a> aims to address this issue by collecting genetic samples from people of diverse backgrounds. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ti50nS7B5vI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The All of Us research program seeks to conduct research that is more representative of a diverse population.</span></figcaption>
</figure>
<p>Another limitation of direct-to-consumer PGx tests is that they can predict drug response based only on your genetics. <a href="https://my.clevelandclinic.org/health/diagnostics/21093-pharmacogenomics">Lifestyle and environmental factors</a> such as your age, liver or kidney function, tobacco use, drug interactions and other diseases can heavily influence how you may respond to medication. For example, leafy greens with high amounts of vitamin K can <a href="https://www.pennmedicine.org/updates/blogs/heart-and-vascular-blog/2015/june/consistency-not-avoidance-the-truth-about-blood-thinners-leafy-greens-and-vitamin-k">lower the effectiveness</a> of the blood thinner warfarin. But PGx tests don’t take these factors into account.</p>
<p>Finally, your PGx results may predict that you may respond to medications differently, but this does not guarantee that the medication won’t have its intended effect. In other words, PGx testing is predictive rather than deterministic.</p>
<h2>Risks of PGx testing</h2>
<p>PGx testing carries the risk of not telling the whole story of drug response. If variations within the gene are not found, the testing company often assumes the proteins those genes code for function normally. Because of this assumption, someone carrying a rare or unknown variant may receive inaccurate results.</p>
<p>It may be tempting for some people to see their results and want to change their dose or discontinue their medications. However, this can be dangerous. Abruptly stopping some medications may cause withdrawal effects. Never change the way you take your medications without consulting your pharmacist and physician first.</p>
<p>Sharing your PGx test results with all the clinicians involved in your care can help prevent medication failure and improve safety. Pharmacists are increasingly trained in pharmacogenomics and can serve as a resource to address medication-related questions or concerns.</p>
<p>PGx tests that are not authorized by the Food and Drug Administration cannot be clinically interpreted and therefore cannot be used to inform prescribing. Results from these tests should not be added to your medical record.</p>
<h2>Benefits of PGx testing</h2>
<p>Direct-to-consumer PGx testing can empower patients to advocate for themselves and be an active participant in their health care by increasing access to and knowledge of their genetic information.</p>
<p>Patients’ knowledge of their PGx genetic profile has the potential to improve treatment safety. For example, a 2023 study of over 6,000 patients in Europe found that those who used their PGx results to guide medication therapy were <a href="https://doi.org/10.1016/s0140-6736(22)01841-4">30% less likely</a> to experience adverse drug reactions.</p>
<p>Most PGx test results stay valid throughout a patient’s life, and <a href="https://mhealthfairview.org/services/pharmacogenomics">retesting is not needed</a> unless additional genes or variants need to be evaluated. As more research on gene variants is conducted, prescribing recommendations may be updated. </p>
<p>Overall, genetic information from direct-to-consumer PGx tests can help you collaborate with health care professionals to select more effective medications with a lower risk of side effects.</p><img src="https://counter.theconversation.com/content/209312/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Genetic testing can help take the guesswork out of finding the right treatment. For certain diseases. To an extent.Kayla B. Rowe, Fellow in Clinical Pharmacogenomics, University of PittsburghLucas A. Berenbrok, Associate Professor of Pharmacy and Therapeutics, University of PittsburghPhilip Empey, Associate Professor of Pharmacogenomics, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124202023-09-04T17:37:53Z2023-09-04T17:37:53ZDogs don’t see life through rose-coloured glasses, nor in black and white<p>For a few months now, I’ve been treating six-year-old Samuel, who has the beginnings of myopia. He’s very quick for his age and often asks me questions about tests I give him, and about what I see inside his eyes. </p>
<p>But the last question surprised me. </p>
<p>Samuel knows that some people, like his father, don’t see colours well. But what about his little poodle, Scotch, he asked?</p>
<p>I’m not a veterinarian and don’t want to intrude on their domain of expertise. However, as an optometrist, I can offer some insights that might help answer Samuel’s question. </p>
<h2>Cones and rods</h2>
<p>Ambient light is composed of <a href="https://www.britannica.com/science/photon">particles (photons)</a>, which line up in rays. Light rays travel and strike objects. Some rays are absorbed, while others are reflected, depending on the characteristics of their surfaces and the composition of their materials. The wavelengths of the reflected rays determine the colour of the object as it is perceived by the eye. </p>
<p>Like everything about human vision, colour perception is complex. The retina, the sensitive part that lines the back of the eye, has two types of photon receptors: cones and rods. The cones, in the centre of the retina (fovea), perceive bright light and are <a href="https://askabiologist.asu.edu/rods-and-cones">responsible for colour perception</a>.</p>
<p>There are three types of cones. Each type contains a specific photo-pigment called opsin, which defines its nature. The opsin is produced under the influence of specific genes. The shortest opsin (“Cone S” for <em>short</em>) reacts mainly to blue light (420 nm). The longer one (“Cone L”) is more sensitive to orange-red light (560 nm) and the one in between (“Cone M” for <em>middle</em>) <a href="https://opentextbc.ca/biology/chapter/17-5-vision/">is activated in the presence of green (530 nm)</a>.</p>
<p>However, each cone reacts to each of the rays entering the eye. For example, a red ball will produce a weak response from the S cone (3/10), a slightly stronger response from the M cone (5/10) and a <a href="https://opentextbc.ca/biology/chapter/17-5-vision/">strong response from the L cone</a> (8/10). </p>
<p>The brain combines the signals emitted by each of these cones to form the colour it perceives. So, in the previous example, the perceived colour would be coded 3-5-8, corresponding to what we know as red. A pink colour might have the code 4-6-6, and blue, 8-6-3. Each combination of the 3-cone signals is unique, which allows us to appreciate different hues in all their variations. </p>
<p>That is, as long as the genetic code is intact. </p>
<p>The genes associated with colour vision can be mutated or defective, in which case the person will be partially or completely impaired. The best known of these anomalies is colour blindness (red-green deficiency or daltonism).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="perception of a plant according to a colour-blind person" src="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Colour blindness is associated with difficulty in perceiving red and green.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>And what about animals?</h2>
<p>Colour vision, in humans as in animals, <a href="https://www.discoverwildlife.com/animal-facts/animal-vision-how-do-animals-see/">has developed throughout evolution</a> and results from the needs of each species according to their environment, the prey they hunt and the threats they need to avoid.</p>
<p>For example, birds have a fourth opsin that allows them to see ultraviolet (UV) light. Humans cannot perceive this light because our crystalline (internal) lens <a href="https://www.nwf.org/Magazines/National-Wildlife/2012/AugSept/Animals/Bird-Vision">filters UV rays</a>. UV rays influence birds’ behavioural decisions, including foraging and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0065345408601059#:%7E:text=Publisher%20%20Summary,light%2C%20depending%20on%20the%20species.">their choice of a mate</a>.</p>
<p>So the colour vision of birds is more complex, with the result that the pigeon, which can perceive a myriad of colours, wins the <a href="https://nuscimagazine.com/the-world-through-the-eyes-of-a-pigeon/#:%7E:text=Though%20this%20range%20of%20vision,is%20one%20of%20these%20animal">award for best color vision among all species</a>.</p>
<p>Insects also perceive UV light. This function is essential for them to spot pollen, although their colour vision is very poor. Their eyes are made up of multiple lenses (ommatidia) that perceive <a href="https://www.mpg.de/14337047/how-flies-see-the-world">more movement than colour</a>. That’s much more practical while in fast flight.</p>
<p>Most forest-dwelling mammals have only two opsins. That’s because they lost the one associated with orange-red over the course of evolution. This explains why, unlike humans, these animals don’t perceive the orange bibs of hunters. </p>
<p>Snakes, on the other hand, are more sensitive to red and infrared light, thanks to their infrared receptors. This is an advantage when it comes to spotting prey, as <a href="https://phys.org/news/2006-08-snakes-vision-enables-accurate-prey.html">they can distinguish their heat even at night</a>. </p>
<p>Unsurprisingly, it’s the monkey that’s closest to the human, with its three opsins. It is said to be trichromatic. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="close-up of a black dog's eyes" src="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dogs only perceive yellow-green and violet-blue. Colours are perceived as paler, like pastels.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Back to Scotch</h2>
<p>The vision of dogs — such as our friend Scotch — is <a href="https://ophtalmoveterinaire.com/maladies_oculaires/vision-comment-voit-mon-chien/#:%7E:text=For%20r%C3%A9sumer%2C%20the%20vision%20of,for%20his%20life%20of%20dog.">quite different</a>. </p>
<p>Unlike humans, dogs’ eyes are located on the side of the skull. As a result, dogs have a wider field of vision (250 to 280 degrees), but less simultaneous vision. </p>
<p>So Scotch’s vision of movement is well developed throughout his visual field. But his central vision is actually six times weaker than ours. This is equivalent to the vision of a very myopic person not wearing glasses. Why? Because the dog’s retina contains no fovea, and therefore fewer cones. </p>
<p>But while dogs eyes have fewer cones, they have more rods. And as an added bonus, they have an extra layer of the retina, called the tapetum lucidum — or carpet. When combined, these ingredients mean dogs see better in dim light and at night. This layer receives light and reflects it back onto the retina for a second exposure. This explains why your dog’s eyes seem to glow at night.</p>
<p>When it comes to colours, dogs are dichromats. They perceive only yellow-green and violet-blue. Colours are perceived paler, like pastels. And some colours don’t contrast: that’s why a red ball on green grass will appear to them as pale yellow on a grey background, with little contrast.</p>
<p>So it’s possible, depending on the colour of the ball, that Scotch will not see it, and as a result, will gaze up at Samuel with a lost look. As for the infrared, he perceives heat through his nose, not through his eyes.</p>
<p>Cats are also dichromats. Their vision is therefore similar to that of dogs, but their colour palette is different — more oriented towards violet and green. Having no perception of red-green, they are essentially colour-blind. They are also very short-sighted. Their clear vision is limited to a few meters in front of them.</p>
<p>Throughout cats’ evolution, other senses came to compensate for this. Among other things, although they only perceive certain contrasts, they are <a href="https://www.wired.com/2013/10/cats-eye-view/">formidable at perceiving movement</a>. Mice move quickly! </p>
<p>Every species adapts to its environment, and humans are no exception. Who knows what our colour vision will be like 500 years from now, after we’ve been exposed to more and more electronic devices and artificial colours? </p>
<p>But that’s a question for Samuel to answer when he’s older.</p><img src="https://counter.theconversation.com/content/212420/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Your faithful companion sees the world differently than you do, but it’s a mistake to assume dogs only see black, white and shades of grey.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2120732023-08-27T13:32:44Z2023-08-27T13:32:44ZLearning from failures: Support for scientific research needs to include when things don’t work out<figure><img src="https://images.theconversation.com/files/544660/original/file-20230824-17-fr9wys.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C2378%2C1084&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A failed experiment led to researchers showing that assumptions about chromosomal behaviour were wrong.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/learning-from-failures-support-for-scientific-research-needs-to-include-when-things-dont-work-out" width="100%" height="400"></iframe>
<p>The cellular processes involved in gene regulation can be unexpectedly complicated. The expression of genes — the when, where and how much of gene activity — underlies all of biology, but is surprisingly poorly understood. </p>
<p>A recent paper published by our research group <a href="https://doi.org/10.1093/genetics/iyac181">generates as many questions as answers</a>, but gives some explanations to possible mechanisms underlying the tangle of gene function. And notably, this published research shouldn’t exist, given the way we generally fund and support scientific research.</p>
<h2>Complexity and genetic regulation</h2>
<p>Biological complexity — the gloriously complicated and convoluted living world around us — is driven by regulation and specificity. </p>
<p>Essentially, every cell in a multicellular organism has the same set of genes known as their genome. What gives cells their unique identity — what makes a skin cell a skin cell and not a muscle cell — is their specific set of genes that are turned on or off. This regulation process is incredibly specific but frustratingly messy, and follows staggeringly tangled webs of rules. </p>
<p>This complexity makes the details of regulation of gene activity one of the great unknowns of modern biology.</p>
<p>In our paper, we explore how chromosomes physically interact and share information, how that sharing substantially modifies gene expression, and how that modification varies drastically between individuals. All three of these points explain some of the complexity in gene expression, but all three have been largely ignored in conventional modelling of gene regulation.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an x shaped 3-d figure coloured pink and yellow floating among other similar blue shapes" src="https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544713/original/file-20230825-27-l9lc4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Geneticists have long assumed that chromosomes operate independently, but a failed research experiment showed that this was not the case.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Geneticists have been taught that chromosomes are independent, don’t modify each other’s expression and that gene expression is similar between individuals. Except they aren’t, they do and it isn’t. </p>
<h2>Chromosomal communication</h2>
<p>In a process called <a href="https://doi.org/10.1016/j.cub.2017.08.001">transvection</a>, pairs of chromosomes physically couple, modifying the expression of the genes they contain. We studied the phenomena in fruit flies using an unusual genetic situation we had created by pairing a series of chromosomes with small genetic deletions that inactivate a gene with wild, functional chromosomes. </p>
<p>Other labs have shown that chromosome pairing is part of <a href="https://doi.org/10.1038/s41467-022-31737-y">normal gene regulation</a> and <a href="https://doi.org/10.1016/j.celrep.2022.111910">development</a>. But pairing errors similar to the ones in our study do occur, and they drive at least one type of <a href="https://doi.org/10.1371/journal.pgen.1000176">human cancer</a>. </p>
<p>Transvection is <a href="https://doi.org/10.1016/j.gde.2016.03.002">a widespread process</a> and a powerful example of the hidden complexity of gene regulation. </p>
<p>It is also an example of research we would not have pursued if not for some uncommon direction and mentoring Thomas Merritt, a co-author of this article, received just before starting his own lab.</p>
<p>Our transvection project started as a <a href="https://doi.org/10.1534/genetics.105.048249">failed experiment</a> while Merritt worked in evolutionary geneticist Walt Eanes’s <a href="https://life2.bio.sunysb.edu/ee/eaneslab/">lab at Stony Brook University</a>. As part of a study on metabolic interactions in flies, Merritt had edited a gene to produce a specific level of protein activity. Although the editing worked, there was much higher than expected levels of protein <a href="https://doi.org/10.1534/genetics.111.133231">and gene activity</a>. The experiment had failed. </p>
<p>Fortunately, Eanes explicitly guided researchers under his mentorship to pay attention to the unexpected, including failed experiments, and use them as an opportunity to question assumptions. </p>
<p>Two decades later, <a href="http://www.boscogeneticslab.com/people2">working alongside</a> <a href="https://www.bowdoin.edu/profiles/faculty/jbateman/">other scientists</a>, we’re still <a href="https://www.transvection.org/">finding new complications in genetics</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a small fly" src="https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544715/original/file-20230825-17-rz04it.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Studying the genome of Drosophila melanogaster reveals how chromosomes interact with and affect each genetic expression.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Failed experiments and scientific assumptions</h2>
<p>That initial experiment had failed — but it had done so for a very interesting reason. That failed experiment, and the series of studies that followed it, showed that what geneticists typically think of as “<a href="https://wyss.harvard.edu/news/light-shed-on-century-old-riddle-of-chromosome-pairing/">independent</a>” chromosomes actually interact with each other through direct physical connections.</p>
<p>That failed experiment illuminated a world of complex regulatory control. Not only do genes have incredibly complex on/off switches, these switches sometimes work across and between chromosomes. </p>
<p>Handled well, these unexpected failures in the lab pushed us to question the assumptions that led to the unexpected result. Here, the failed experiment forced us to rethink the independence of chromosomes. </p>
<p>Our further studies explored how this genetic conversation was dynamic, changed <a href="https://doi.org/10.1534/g3.114.012484">in response to the environment</a> and differed between <a href="https://doi.org/10.1534/genetics.111.133231">individuals</a>.</p>
<h2>Individual variation</h2>
<p>The dynamic gene regulation and individual variation that allows multicellularity is also a central player in disease and individuality. For example, why do some people, but not others, respond to cancer treatments or even fall victim to cancer in the first place? </p>
<p>A better appreciation of individual variation is one of the major advances of our paper. Knowing that the amount of communication between chromosomes varies substantially across individuals and our work begins to shed light on the genes and mechanisms behind that variation. </p>
<p>These are important steps towards a more complete understanding of gene regulation and the misregulation that leads to diseases like <a href="https://openoregon.pressbooks.pub/mhccmajorsbio/chapter/cancer-and-gene-regulation/">cancer</a>. </p>
<h2>Dynamic science</h2>
<p>Science advances when scientists push boundaries and explore, not when we repeat or timidly inch forward. Too often we try to avoid or prevent failure. Funding agencies may also hesitate to fund projects seen as <a href="https://www.science.org/content/article/audacity-part-3-funding-audacious-science">risky</a>. </p>
<p>Science needs a culture that promotes risk and exploring the unexpected.</p>
<p>And while we turn to science to address emerging crises, we are not supporting the necessary scientific development. Think of the increasingly frequent <a href="https://theconversation.com/canadians-are-unprepared-for-natural-hazards-heres-what-we-can-do-about-it-201863">climate disasters</a>, the <a href="https://theconversation.com/the-quest-for-delicious-decaf-coffee-could-change-the-appetite-for-gmos-153032">challenges of feeding an exploding global population</a>, <a href="https://doi.org/10.1038/s41586-019-1717-y">the ongoing global pandemic</a> and <a href="https://www.nytimes.com/2023/06/16/opinion/cancer-treatment-disparities.html">cancer</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/doctors-are-drowning-in-a-tsunami-of-liver-disease-and-cancer-98061">Doctors are drowning in a tsunami of liver disease and cancer</a>
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<p>All of these issues will require novel solutions and dynamic approaches that scientific funding agencies should <a href="https://www.forbes.com/sites/drdonlincoln/2021/06/28/why-you-should-care-about-federally-funded-science/">acknowledge and support</a>.</p>
<p>Breakthroughs in understanding require dynamic science and scientists who are supported to explore, ask unusual questions and, occasionally, fail in the lab. Sometimes the most important results from an experiment are the questions it forces us to ask.</p><img src="https://counter.theconversation.com/content/212073/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Merritt receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p><p class="fine-print"><em><span>Teresa Rzezniczak does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A failed experiment led the researchers to question their assumptions and realize that, contrary to popular belief, chromosomes interact with and affect genetic expression.Thomas Merritt, Professor, Chemistry and Biochemistry, Laurentian UniversityTeresa Rzezniczak, PhD Candidate, Biomolecular Sciences, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2117992023-08-24T14:51:27Z2023-08-24T14:51:27ZNew research reveals that Ötzi the iceman was bald and probably from a farming family – what else can DNA uncover?<p>In 1991, hikers came across a body that <a href="https://www.iceman.it/en/the-discovery/">was partially contained in ice</a> high up in the Alpine province of South Tyrol, Italy. Initially thought to be from a recent death, the body was later discovered to be 5,300 years old – from a time known as <a href="https://en.wikipedia.org/wiki/Chalcolithic">the Copper Age</a>.</p>
<p>This amazing find would subsequently become known as Ötzi the iceman. His body and belongings were extensively studied, prompting numerous questions: what was he doing here? Where was he from? How did he live – and die?</p>
<p>Researchers from the Max Planck Institute for Evolutionary Anthropology in Germany have just added another piece to this jigsaw, <a href="https://www.cell.com/cell-genomics/pdfExtended/S2666-979X(23)00174-X">describing the physical appearance of Ötzi</a> based on new DNA information. They say he probably had relatively dark skin and was balding. But how reliable are these predictions and could they be used in forensics?</p>
<p>Much of this depends on the quality of the samples. Ötzi died in the Otzal Alps and was frozen almost immediately, remaining in the permafrost until discovery.</p>
<p><a href="https://www.iceman.it/en/the-iceman/">The body is currently stored in low temperature conditions</a> at the South Tyrol Museum of Archaeology. His unique preservation enabled the sequencing of Ötzi’s whole genome – the complete “instruction booklet” for building a human. The chemical building blocks of DNA are called bases. These are nitrogen-containing chemical compounds called adenine, thymine, cytosine and guanine, known by the letters A, T, C and G. The human genome consists of billions of these bases arranged in different sequences - making up the genetic code.</p>
<p>Much of the genome’s DNA sequence is common to all humans, but there are places where a change from one base to another results in changes to our physical appearance. </p>
<p>The Ötzi paper isn’t the first study that has tried to predict a person’s appearance from ancient remains. King Richard III was killed in the Battle of Bosworth in 1485. When his body was discovered in 2012, under a car park in Leicester, only his bones remained. But it was enough for a team led by Turi King at the University of Leicester to extract <a href="https://www.nature.com/articles/ncomms6631">fragments of DNA from them</a>.</p>
<figure class="align-center ">
<img alt="Representation of the DNA molecule." src="https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&rect=14%2C0%2C4947%2C2799&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544058/original/file-20230822-21-xnyapv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Representation of the DNA molecule.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blue-helix-human-dna-structure-1669326868">Billion Photos / Shutterstock</a></span>
</figcaption>
</figure>
<h2>Crime scene samples</h2>
<p>These fragments, comprising hundreds of DNA bases, were sequenced. They were able to predict his hair and eye colour and he was reliably matched to a living relative – assigning a clear identity to the remains. This means that if I ate an apple and threw the core away, I could also be identified by the DNA I left on the core. </p>
<p>Sequencing a genome, which comprises billions of DNA bases, enables scientists to evaluate regions of the human genome that contribute to appearance. These are known as highly variable regions.</p>
<p>For more than 30 years, forensic scientists have looked at specific highly variable regions in DNA to match these to crime scene samples, or to relatives of a suspect or victim. So how likely is it that DNA from such a sample could accurately paint a picture of me? </p>
<p>Let’s take facial shape. Can forensic scientists build a kind of identikit photo from a crime scene DNA sample? Some efforts have <a href="https://snapshot.parabon-nanolabs.com/">already been taken in this regard</a>. But our understanding of the gene variants involved in face shape are incomplete. </p>
<p>Many of the identikit pictures built from DNA analysis alone <a href="https://snapshot.parabon-nanolabs.com/posters">bear a resemblance</a> to actual images of the individuals. But when DNA is the only evidence available to build a portrait, the prediction of facial appearance can be skewed by body composition which is significantly affected by diet and lifestyle.</p>
<p>However, other aspects of appearance can be predicted with high accuracy: red hair, for example. Base variations in the <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1002/humu.20476">melanocortin receptor 1 (MC1R) gene</a> are linked to red hair, fair skin and freckling. In rarer cases, variations in two other genes <a href="https://www.snpedia.com/index.php/Rs12913832">HERC2</a> and <a href="https://www.snpedia.com/index.php/Rs2378249">PIGU/ASIP</a> are also linked to red hair.</p>
<p>The human genome is packaged into 23 pairs of chromosomes. On chromosome 15 there are many regions which influence eye colour and skin pigmentation. Eye colour can be reliably predicted, with blue eye colour the most accurate. Hair colour can be predicted from DNA, but <a href="https://www.sciencedirect.com/science/article/pii/S1872497312001810">darker shades of hair are more accurately predicted</a> than blonde hair. </p>
<p>Aside from the complications posed by hair dye, predicting blonde hair is complicated because some individuals have very blonde hair in childhood that darkens to light brown with the onset of adulthood. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-does-genetics-explain-non-identical-identical-twins-55479">How does genetics explain non-identical identical twins?</a>
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<h2>Environmental factors</h2>
<p>Several genes contribute to produce hair pigments and a spectrum of hair colour is seen in humans, ranging from light blonde to black. <a href="https://www.sciencedirect.com/science/article/pii/S1872497312001810">Commercially sold laboratory kits such as Hirisplex</a> can simultaneously evaluate several DNA regions to predict the hair and eye colour from a biological sample. However, unlike eye colour, hair colour prediction from DNA is only of value until midlife, when the natural processes of ageing lead to greying or white hair. </p>
<p>These processes also lead to hair loss in some people and more than 300 gene variants have been linked to baldness. Future research should determine more clearly how these gene variants affect hair density. However, stress, diet, medication, and disease, in addition to genetics, all influence hair loss. </p>
<p>Individual DNA bases can become chemically modified as we age. This is known as an epigenetic change. Identical twins start life with the same DNA, but as they age, some physical differences become apparent.</p>
<p>Some of those differences are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4276927/">due to DNA bases changing</a> as cells divide but most are due to base changes caused by lifestyle and the environment. This is an exciting area of research for understanding ageing and disease. It can also be used as a forensic tool to distinguish between twins.</p>
<p>There is currently a lot of DNA information from people of European origin, but fewer whole genomes exist from populations elsewhere. This can influence the accuracy when scientists try to predict both appearance and ancestry.</p>
<p>More representative data from the rest of the world will therefore enhance studies in forensic archaeology, such as the Ötzi research. It will also have implications for forensics and assist in the identification of missing individuals.</p><img src="https://counter.theconversation.com/content/211799/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Caroline Smith does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We can predict hair and eye colour with reasonable accuracy from DNA, but other characteristics are being investigated.Caroline Smith, Assistant Head, School of Life Sciences, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1847232023-08-22T21:54:17Z2023-08-22T21:54:17ZNew research into genetic mutations may pave the way for more effective gene therapies<figure><img src="https://images.theconversation.com/files/543314/original/file-20230817-8328-bdaz8a.jpg?ixlib=rb-1.1.0&rect=44%2C0%2C5000%2C3315&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A lab dish containing embryos that have been injected with Cas9 protein and PCSK9 sgRNA is seen in a laboratory in Shenzhen in southern China's Guangdong province.</span> <span class="attribution"><span class="source">(AP Photo/Mark Schiefelbein)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/new-research-into-genetic-mutations-may-pave-the-way-for-more-effective-gene-therapies" width="100%" height="400"></iframe>
<p>Consider a living cell, which can have thousands of genes. Now think of these genes as dials that can be tweaked to change how the cell grows in a given environment. Tweaking a gene can either increase or decrease growth, and this is made more complex considering these dials are interconnected with each other, like cogs in a machine. </p>
<p>While scientists are now able to edit genes in laboratory conditions and attempt to produce findings that may lead to cures, evolution has been doing this for billions of years. Evolution is the natural process that turns these dials, allowing populations to adapt. However, unlike scientists, evolution turns these dials randomly as mutations affect the function of genes.</p>
<p>One underlying hypothesis in evolutionary theory — the evolutionary contingency hypothesis — has been that this tuning can have chaotic behaviours. Or, in other words, dials tweaked early in the process can dramatically alter later evolutionary potential.</p>
<p>Stephen Jay Gould was a famous proponent of this theory, arguing in his 1989 book <a href="https://wwnorton.com/books/9780393307009"><em>Wonderful Life</em></a> that since beneficial mutations occur randomly, chance must play an important role in evolutionary diversification.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/does-our-dna-really-determine-our-intelligence-and-health-199266">Does our DNA really determine our intelligence and health?</a>
</strong>
</em>
</p>
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<p>If this hypothesis is true, it affects how scientists should edit genes in the laboratory as they will face the chaotic interconnections of our cells. Our work set out to test this hypothesis.</p>
<h2>Resolving an evolutionary paradox</h2>
<p>We can observe the process of evolution in the laboratory under extremely well-controlled conditions. We have done so by growing populations of micro-organisms for hundreds — <a href="https://doi.org/10.7554/eLife.63910">even thousands — of days</a>. </p>
<p>Since these organisms divide and reproduce so quickly, this process represents thousands of generations of growth. These experiments have allowed us to pinpoint <a href="https://doi.org/10.1038/s41586-019-1749-3">precisely when</a>, and how, beneficial mutations co-occur and compete to take over the population.</p>
<figure class="align-center ">
<img alt="Image of a human genome." src="https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543310/original/file-20230817-41912-psfxhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Image readout of a human genome.</span>
<span class="attribution"><span class="source">(NHGRI via AP)</span></span>
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<p>One striking observation from every single one of these experiments is that increases in fitness slow down over time at a rate that is surprisingly reproducible. Despite accumulating different mutations, different populations show remarkably predictable diminishing returns in how fast they adapt.</p>
<p>In contrast with the seemingly chaotic behaviour of mutations, fitness or growth changes are highly predictable. This has led many to hypothesize that this order of mutation is an <a href="https://doi.org/10.3389/fgene.2015.00099">inherent consequence</a> of the way biological systems have evolved. </p>
<p>This striking hypothesis is at odds with the idea that the <a href="https://doi.org/10.1038/s41559-020-01286-y">specifics of an organism’s biology matter for evolution</a>. In other words, it has been difficult to prove that the order in which evolution turns dials has any impact on the future.</p>
<h2>The answer to the paradox</h2>
<p>My team was able to show that the answer to resolving this paradox lies within the interconnected gene network of the cell itself. </p>
<p>For evolution to work, the dial-tuning must be precise: even if the net outcome is beneficial, adjusting one set of linked dials can trickle down and affect other previously correctly placed dials. As evolution continues, the probability of breaking harmoniously-tuned dials grows. This seemingly simple principle explains why the rate of evolutionary improvements typically slows down over time. </p>
<figure class="align-center ">
<img alt="A tray containing human DNA samples ready for genetic sequencing." src="https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543312/original/file-20230817-23-a743da.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A tray containing human DNA samples ready for genetic sequencing.</span>
<span class="attribution"><span class="source">(AP Photo/Patricia McDonnell)</span></span>
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</figure>
<p>Resolving this paradox experimentally was not an easy task. After all, how can one show the entanglement of dials within the cell? <a href="https://doi.org/10.1126/science.abm4774">In our recent study</a>, we tackled this challenge by systematically trying out every possible combination of 10 key beneficial mutations and looking at how they affect the growth of cells.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/human-genome-editing-offers-tantalizing-possibilities-but-without-clear-guidelines-many-ethical-questions-still-remain-200983">Human genome editing offers tantalizing possibilities – but without clear guidelines, many ethical questions still remain</a>
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</em>
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<hr>
<p>By testing out combinations of mutations, we were able to reliably understand which mutations were entangled together (this entanglement is known as epistasis) and for just 10 mutations, over 1,000 combinations had to be generated.</p>
<h2>How this affects genetic precision medicine</h2>
<p>Current futuristic technologies tout the ability to generate precise single mutations within our own genomes with the hope that this can be used to repair non-functional genetic variants. For example, <a href="https://doi.org/10.1038/s41586-019-1711-4">prime editing</a> is an effective “search-and-replace” genome editing technology.</p>
<p>One important concern with these approaches is they can introduce undesired mutations at the same time. However, even as scientists solve these concerns, the field of human genetics has often <a href="https://doi.org/10.1038/s41576-019-0127-1">overlooked the importance of the interconnectedness of genes</a>.</p>
<p>Our study demonstrates that bioengineers should think not only about the effect a mutation has on the gene it is in, but also about the effect of the mutation in the context of all other variations in our genomes. Altering the function of any of our genes can affect our interconnected cellular networks. </p>
<p>This is compounded by the fact that all of us carry hundreds of extremely rare variants, which means each of us carries a unique interconnected network of genes. These personalized networks make us who we are. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/somatic-genome-editing-therapies-are-becoming-a-reality-but-debate-over-ethics-equitable-access-and-governance-continue-201234">Somatic genome editing therapies are becoming a reality – but debate over ethics, equitable access and governance continue</a>
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</p>
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<p>Genome interpretation is at the heart of genetic testing for disease. And while scientists have made some progress in identifying key pathogenic genetic variants (those that can cause disease), our findings demonstrate that classifying a variant as pathogenic or benign requires us to also understand how the other genetic dials in our cells are tuned.</p><img src="https://counter.theconversation.com/content/184723/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alex Nguyen Ba receives funding from the Natural Sciences and Engineering Research Council of Canada. </span></em></p>New research sheds light on the interconnected nature of the human genome and what this means for future gene therapies.Alex Nguyen Ba, Assistant Professor, Biology, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2088022023-08-17T10:50:21Z2023-08-17T10:50:21ZHow biological differences between men and women alter immune responses – and affect women’s health<figure><img src="https://images.theconversation.com/files/539557/original/file-20230726-21-jhiwex.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3849%2C2568&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/wooden-cubes-image-male-female-gender-2175270281">Fida Olga/Shutterstock</a></span></figcaption></figure><p>Most people will have heard the term “man flu”, which refers to men’s perceived tendency to exaggerate the severity of a cold or a similar minor ailment. </p>
<p>What most people may not know is that, generally speaking, women mount stronger <a href="https://pubmed.ncbi.nlm.nih.gov/36121220/">immune responses</a> to infections than men. Men are <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005374">more susceptible</a> to infections from, for example, HIV, hepatitis B, and <em>Plasmodium falciparum</em> (the parasite responsible for malaria). </p>
<p>They can also have more severe symptoms, with evidence showing they’re more likely to be <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005374">admitted to hospital</a> when infected with hepatitis B, tuberculosis, and <em>Campylobacter jejuni</em> (a bacteria that causes gastroenteritis), among others.</p>
<p>While this may be positive for women in some respects, it also means women are at <a href="https://www.nature.com/articles/nri2815">greater risk</a> of developing chronic diseases driven by the immune system, known as immune-mediated inflammatory diseases.</p>
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<img alt="" src="https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542294/original/file-20230811-4652-hn8w80.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of <a href="https://theconversation.com/uk/topics/womens-health-matters-143335">Women’s Health Matters</a>, a series about the health and wellbeing of women and girls around the world. From menopause to miscarriage, pleasure to pain the articles in this series will delve into the full spectrum of women’s health issues to provide valuable information, insights and resources for women of all ages.</em></p>
<p><em>You may be interested in:</em></p>
<p><em><a href="https://theconversation.com/the-orgasm-gap-and-why-women-climax-less-than-men-208614">The orgasm gap and why women climax less than men</a></em></p>
<p><em><a href="https://theconversation.com/five-old-contraception-methods-that-show-why-the-pill-was-a-medical-breakthrough-207572">Five old contraception methods that show why the pill was a medical breakthrough
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<p><em><a href="https://theconversation.com/science-experiments-traditionally-only-used-male-mice-heres-why-thats-a-problem-for-womens-health-205963">Science experiments traditionally only used male mice – here’s why that’s a problem for women’s health</a></em></p>
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<p>Here we will explore how biological factors influence immune differences between the sexes and how this affects women’s health. While we acknowledge that both sex and gender may affect immune responses, this article will focus on biological sex rather than gender. </p>
<h2>Battle of the sexes</h2>
<p>There are differences <a href="https://www.nature.com/articles/nri.2016.90">between the sexes</a> at every stage of the immune response, from the number of immune cells, to their degree of activation (how ready they are to respond to a challenge), and beyond.</p>
<p>However, the story is more complicated than that. Our immune system evolves throughout our lives, learning from past experiences, but also responding to the physiological challenges of getting older. As a result, <a href="https://www.nature.com/articles/nri.2016.90">sex differences</a> in the immune system can be seen from birth through puberty into adulthood and <a href="https://academic.oup.com/jleukbio/advance-article/doi/10.1093/jleuko/qiad053/7190870">old age</a>.</p>
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<strong>
Read more:
<a href="https://theconversation.com/discovery-of-gene-associated-with-20-autoimmune-diseases-leads-to-promising-drug-trials-131957">Discovery of gene associated with 20 autoimmune diseases leads to promising drug trials</a>
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</em>
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<p>Why do these differences occur? The first part of answering this question involves the X chromosome. Females have two X chromosomes, while males have one X and one Y chromosome. The <a href="https://pubmed.ncbi.nlm.nih.gov/20651746/">X chromosome</a> contains the largest number of immune-related genes. </p>
<p>The X chromosome also has <a href="https://link.springer.com/article/10.1007/s00018-020-03526-7">around 118 genes</a> from a gene family that are able to stop the expression of other genes, or change how proteins are made, including those required for immunity. These gene-protein regulators are known as microRNA, and there are only <a href="https://pubmed.ncbi.nlm.nih.gov/24808907/">two microRNA genes</a> on the Y chromosome.</p>
<p>The X chromosome has <a href="https://www.genome.gov/about-genomics/fact-sheets/X-Chromosome-facts">more genes overall</a> (around 900) than the Y chromosome (around 55), so female cells have evolved to switch off one of their X chromosomes. This is not like turning off a light switch, but more like using a dimmer. </p>
<p>Around <a href="https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-019-5507-6">15-25% of genes</a> on the silenced X chromosome are expressed at any given moment in any given cell. This means female cells can often express more immune-related genes and gene-protein regulators than males. This generally means a faster clearance of pathogens in females than males.</p>
<figure class="align-center ">
<img alt="Three women laughing together outdoors." src="https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539933/original/file-20230728-19-fesqbz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Women have two X chromosomes, which partly explains why the female immune system works differently.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mature-female-friends-socializing-backyard-together-583329838">Monkey Business Images/Shutterstock</a></span>
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<p>Second, men and women have <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2020.604000/full">varying levels</a> of different sex hormones. Progesterone and testosterone are broadly considered to limit immune responses. While both hormones are produced by males and females, progesterone is found at higher concentrations in non-menopausal women than men, and testosterone is much higher in men than women. </p>
<p>The role of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533072/">oestrogen</a>, one of the main female sex hormones, is more complicated. Although generally oestrogen <a href="https://www.sciencedirect.com/science/article/abs/pii/S000887491500026X?via%3Dihub">enhances immune responses</a>, its levels vary during the menstrual cycle, are high in pregnancy and low after menopause. </p>
<p>Due in part to these genetic and hormonal factors, pregnancy and the years following are associated with heightened immune responses to external challenges such as infection. </p>
<p>This has been regarded as an <a href="https://www.nature.com/articles/nri.2016.90">evolutionary feature</a>, protecting women and their unborn children during pregnancy and enhancing the mother’s survival throughout the child-rearing years, ultimately ensuring the survival of the population. We also see this pattern in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2628977/">other species</a> including insects, lizards, birds and mammals. </p>
<h2>What does this all mean?</h2>
<p>With women’s heightened immune responses to infections comes an increased risk of certain diseases and prolonged immune responses after infections.</p>
<p>An <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3328995/">estimated 75-80%</a> of all immune-mediated inflammatory diseases <a href="https://pubmed.ncbi.nlm.nih.gov/32542149/">occur in females</a>. Diseases more common in women include multiple sclerosis, <a href="https://www.nature.com/articles/nri2815">rheumatoid arthritis</a>, lupus, Sjogren’s syndrome, and <a href="https://www.nature.com/articles/nri.2016.90">thyroid disorders</a> such as Graves disease.</p>
<p>In these diseases, the immune system is continuously fighting against what it sees as a foreign agent. However, often this perceived threat is not a foreign agent, but cells or tissues from the host. This leads to tissue damage, pain and immobility.</p>
<p>Women are also prone to chronic inflammation following infection. For example, after infections with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818468/">Epstein Barr virus</a> or <a href="https://www.liebertpub.com/doi/10.1089/jwh.2008.1193">Lyme disease</a>, they may go on to develop <a href="https://www.nhs.uk/conditions/chronic-fatigue-syndrome-cfs/">chronic fatigue syndrome</a>, another condition that affects more women than men.</p>
<p>This is one possible explanation for the heightened risk among <a href="https://www.frontiersin.org/articles/10.3389/fresc.2023.1122673/full">pre-menopausal women</a> of developing long COVID following infection with SARS-CoV-2, the virus that causes COVID. </p>
<p>Research has also revealed the presence of auto-antibodies (antibodies that attack the host) in patients with long COVID, suggesting it might be an <a href="https://www.sciencedirect.com/science/article/pii/S1568997221000550">autoimmune disease</a>. As women are more susceptible to autoimmune conditions, this could potentially explain the sex bias seen. </p>
<p>However, the exact causes of long COVID, and the reason women may be at greater risk, are yet to be defined. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/long-covid-female-sex-older-age-and-existing-health-problems-increase-risk-new-research-185911">Long COVID: female sex, older age and existing health problems increase risk – new research</a>
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<p>This paints a bleak picture, but it’s not all bad news. Women typically mount <a href="https://pubmed.ncbi.nlm.nih.gov/24966191/">better vaccine responses</a> to several common infections (for example, influenza, measles, mumps, rubella, hepatitis A and B), producing higher antibody levels than men. </p>
<p>One study showed that women vaccinated with half a dose of flu vaccine produced the same amount of antibodies compared to men vaccinated with <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/773453">a full dose</a>. </p>
<p>However, these responses <a href="https://www.nature.com/articles/nri.2016.90">decline as women age</a>, and particularly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3954964/">after menopause</a>. </p>
<p>All of this shows it’s vital to consider sex when designing studies examining the immune system and treating patients with immune-related diseases.</p><img src="https://counter.theconversation.com/content/208802/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Helen McGettrick receives funding from the Medical Research Council, Biotechnology and Biological Sciences Research Council, Wellcome Trust, F Hoffmann-La Roche Ag, Versus Arthritis, Dompè Pharmaceuticals Ltd, Novartis, Chernajovsky Foundation, British Heart Foundation, Pfizer. </span></em></p><p class="fine-print"><em><span>Asif Iqbal receives funding from, Wellcome Trust, F Hoffmann-La Roche, Chernajovsky Foundation, British Heart Foundation. </span></em></p>Women are more likely to develop chronic diseases driven by the immune system.Helen McGettrick, Reader in Inflammation and Vascular Biology, University of BirminghamAsif Iqbal, Associate Professor in Inflammation Biology, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.