tag:theconversation.com,2011:/id/topics/animal-genetics-22806/articlesAnimal genetics – The Conversation2022-02-10T14:04:04Ztag:theconversation.com,2011:article/1762682022-02-10T14:04:04Z2022-02-10T14:04:04ZGenetic diversity is key in conservation: here’s a list to help manage lion populations<figure><img src="https://images.theconversation.com/files/445057/original/file-20220208-19-3ob7k4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lion diversity is distributed across four different evolutionary lineages: East Africa, Southern Africa, West/Central Africa and India.</span> <span class="attribution"><span class="source">Laura Bertola</span></span></figcaption></figure><p>Biodiversity exists at three different levels: diversity between ecosystems, between species, and within species. The genetic diversity that exists within a species is what enables the species to evolve and adapt. Many studies have shown that genetic diversity provides resilience against extinction. </p>
<p>Conserving biodiversity, then, means more than preventing the extinction of a species. It also means preventing loss of genetic diversity within that species. </p>
<p>One way of losing genetic diversity is when populations go extinct in a particular location and specific <a href="https://www.pnas.org/content/114/30/E6089">genetic lineages</a> come to an end. Another way is when individuals in small and isolated populations become more strongly related to each other. It can lead to <a href="https://www.nature.com/articles/hdy2009155">inbreeding depression</a> – when offspring are less fertile and less likely to survive. This has been described for many species, including lions.</p>
<p>Conservation managers can intervene to support genetic diversity in a species. For example, to expand and restore the natural range of a species, managers can release individual animals in an area where they have previously gone extinct. Or if a population has become so small and isolated that its genetic health is in danger, managers may bring in new, unrelated individuals to mimic natural migration between populations. </p>
<p>In practice, though, these initiatives usually focus on the population or numbers of individuals. They don’t always take genetic information <a href="https://theconversation.com/why-moving-south-african-lions-to-rwanda-is-not-without-problems-46273">into account</a>. That’s dangerous. When managers don’t choose genetically suitable animals, moving them to another population can fail. It can even have a negative influence on overall biodiversity. </p>
<p>In African wildlife management, individual animals for translocations are often sourced from <a href="https://www.mdpi.com/2673-7159/1/2/11">South Africa</a>. The country has many intensively managed parks, which regularly have surpluses of certain species. But shipping South African animals across the continent and reintroducing them far away from their original population could have adverse effects for biodiversity. If they integrate into resident populations at the target site, they may spread their genes there, influencing the genetic makeup of the local population. This could even lead to the loss of genetic adaptation to local environments. And if it happens on a large scale, across multiple localities, all populations could become similar.</p>
<p>When planning a translocation, the genetic makeup of both the source and target populations needs to be taken into account. Preferably, both populations should be from the same genetic lineage. In this way, the translocation resembles natural migration between populations. </p>
<h2>Lion genetics</h2>
<p>We recently published a scientific article in which we assess available genetic data and its implications for translocations in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/eva.13318">the lion</a>.</p>
<p>The lion has been a popular subject for studying diversity on <a href="https://www.nature.com/articles/srep30807">the genetic level</a>. Lions are a species that many people know and care about, with a vast range throughout sub-Saharan Africa and into India. Genetic data show that lion diversity is distributed across four different evolutionary lineages: East Africa, Southern Africa, West/Central Africa, and India. The first two lineages are grouped together as the southern subspecies, while the latter two are grouped together as the northern subspecies. To conserve the lion in the long term, we need to conserve its genetic diversity.</p>
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<a href="https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lion on the grass with a tree in the background." src="https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=931&fit=crop&dpr=1 600w, https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=931&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=931&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1170&fit=crop&dpr=1 754w, https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1170&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/445058/original/file-20220208-13-1d58z6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1170&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">In less than 40 years, over 1,000 individual live lions have been moved between countries.</span>
<span class="attribution"><span class="source">Laura Bertola</span></span>
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</figure>
<p>In our study, we’ve listed 132 lion populations or conservation units and provided information on genetic assignment, uncertainty and suitability for translocation for each source and target combination.</p>
<p>To get a better insight into the extent and directions of lions being moved around the continent, we also mined trade data from the <a href="https://trade.cites.org/">CITES Trade Database</a>. This records all import and export permits for transboundary trade. There is additional information on the origin of the individuals and the purpose of the transport. The data show that in less than 40 years, over 1,000 individual live lions have been moved between countries, and into countries in which wild lions occur.</p>
<p>We then assessed whether, based on all genetic information that’s currently available, these transports were within or between genetic lineages. We identified three levels of suitability, based on the genetic differentiation between populations. We scored a translocation between subspecies as “unsuitable”, as well as a translocation of “captive” individuals, with unknown genetic background. </p>
<p>We concluded that the vast majority of the translocated lions would be scored as “unsuitable”. That is, they could be a risk to the genetic diversity of lions and to biodiversity more generally.</p>
<h2>Integrating genetics in decision making</h2>
<p>Even though genetic data may be unavailable for some populations, based on our understanding of <a href="https://www.nature.com/articles/srep30807">lion diversity</a> and known locations of the boundaries between different lineages, we can often infer which genetic group they belong to. So genetics can be taken into account, even when genetic data from a particular population is missing. </p>
<p>We hope that the three different suitability levels we’ve provided will help conservation managers to explore different options when making their decisions. We encourage them to follow the natural distribution of genetic diversity in the lion when searching for suitable source populations.</p>
<p>In management interventions there are many other factors that need to be taken into account too – ecological, behavioural and even political. Even though these factors are not taken into account here, we hope that our work provides guidance and support to integrate genetics in future management decisions. </p>
<p>It’s in the interest of the lion, as a species, to focus not just on the persistence of populations, but also on the underlying genetic diversity. This will increase its resilience and adaptability, which is necessary for long-term survival of the species.</p><img src="https://counter.theconversation.com/content/176268/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Bertola 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>When planning a translocation, the genetics of the lion must be taken into account.Laura Bertola, Postdoctoral fellow at Copenhagen University, Leiden UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1663972021-11-23T13:30:30Z2021-11-23T13:30:30ZScientist at work: Endangered ocelots and their genetic diversity may benefit from artificial insemination<figure><img src="https://images.theconversation.com/files/432290/original/file-20211116-25-1e4gv3m.jpg?ixlib=rb-1.1.0&rect=1384%2C1010%2C3607%2C2267&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wild ocelots hunt alone at night.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/ocelot-is-hunting-at-night-at-the-san-francisco-ranch-in-news-photo/1219080513">Wolfgang Kaehler/LightRocket via Getty Images</a></span></figcaption></figure><p>The female ocelot lay anesthetized on the exam table, behind the scenes at the Albuquerque Biopark Zoo. As a veterinarian on the team preparing to artificially inseminate this animal, my palms were sweating at the thought of missing a step, dropping the sperm sample, or finding out our sample did not survive freezing. Any of these possibilities would end the procedure.</p>
<p>It was the first time anyone was trying to produce a pregnancy in a zoo-born female ocelot using sperm recovered from a deceased wild male ocelot. If the July 2021 operation worked, it would give his genes a way to live on past his death. This procedure was an important step in efforts to conserve endangered cat species so they can persist into the future.</p>
<p>Ocelots are medium-sized felines weighing around 20 to 30 pounds (9 to 13 kilograms) with sleek spotted coats. Their diet consists of small mammals, rodents, amphibians, reptiles and birds. Ocelots are primarily solitary cats, most active in the evening from dusk to dawn.</p>
<p>While people manage zoo-housed ocelots’ reproduction to maintain genetic diversity, it’s a different story for their wild relatives. There are <a href="https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T11509A50653476.en">currently only 50 to 80 ocelots</a> (<em>Leopardus pardalis</em>) known to exist in the wild in the U.S., and that population is too small to be sustainable long term. <a href="https://ecos.fws.gov/ecp/species/4474">These endangered animals</a> face ongoing threats of habitat loss and fragmentation, and vehicle strikes. And because of their diminished numbers, they are at risk of inbreeding. </p>
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<a href="https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="street sign warning of ocelot crossing" src="https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432291/original/file-20211116-17-y7xeen.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">With so few individuals left in the wild in the U.S., each ocelot hit by a car could affect the species’ survival.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/ocelot-crossing-road-sign-royalty-free-image/855966216">kzubrycki/iStock via Getty Images Plus</a></span>
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<p>Over the past 25 years, scientists at the <a href="http://cincinnatizoo.org/conservation/crew/">Center for Conservation and Research of Endangered Wildlife</a>, or CREW, led by veterinarian Bill Swanson, have been working on technologies that may eventually help add some more genetic diversity to the wild ocelot population. They’ve <a href="https://doi.org/10.1111/rda.12069">developed and refined techniques</a> for sperm collection, <a href="https://doi.org/10.1530/jrf.0.1060087">frozen storage</a> and <a href="https://doi.org/10.1095/biolreprod.112.105353">artificial insemination of ocelots</a> and other endangered cat species.</p>
<p>These innovations have played a key role in sustaining the genetic diversity of cat populations within zoos. Now, we’re trying to go a step further and apply these techniques in wild ocelots.</p>
<p>By creating gene flow among zoo-based ocelots and wild ocelots in different regions, we can increase the genetic diversity of both populations. With wild ocelots, we hope to combat their declining ability to produce offspring, fight infection and maintain adequate numbers in the wild for conservation of the species in the U.S.</p>
<h2>Salvaging sperm to increase diversity</h2>
<p><a href="https://scholar.google.com/citations?user=JyYbknYAAAAJ&hl=en&oi=ao">As a recently graduated veterinarian</a>, I joined my mentor, Debra Miller, at the University of Tennessee’s Comparative and Experimental Medicine Department and in her work at UT’s Center for Wildlife Health. From there, my interests in wildlife conservation led me to this multi-institutional collaboration focusing on the conservation of wild Texas ocelots.</p>
<p>This project relies on the routine collection and freezing of semen from wild ocelots in the field – usually living animals, but sometimes ones that have been found dead. Our semen stockpile lets us preserve genetic material even if these cats are killed by disease, natural disasters or road collisions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="tanks containing many frozen animal semen samples" src="https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=509&fit=crop&dpr=1 754w, https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=509&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/430877/original/file-20211108-19-fkek42.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=509&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 CREW CryoBioBank at the Cincinnati Zoo currently holds over 20,000 total semen samples from 82 animal species ranging from elephants to salamanders – including 30 cat species/subspecies – at temperatures of -320 F (-196 C) in liquid nitrogen.</span>
<span class="attribution"><span class="source">Tom Uhlman</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>For the artificial insemination procedure this past summer, the sperm donor was <a href="https://tpwd.texas.gov/huntwild/wild/species/ocelot/">a Texas ocelot</a> that died after being hit by a car. While this male’s death was a tragedy, there is a chance his genes may live on in future offspring thanks to the quick report of his death and the retrieval, shipping and processing of his gonads.</p>
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<a href="https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Placing cryovial of animal semen in a storage tank" src="https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=708&fit=crop&dpr=1 600w, https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=708&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=708&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=890&fit=crop&dpr=1 754w, https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=890&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/430875/original/file-20211108-21-1kd1vi0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=890&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">Thirteen 0.25-milliliter semen straws are in each goblet tube within the canisters inside the frozen storage tank.</span>
<span class="attribution"><span class="source">Tom Uhlman</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Back at CREW in Cincinnati, Bill Swanson worked to recover the cat’s sperm for future artificial insemination procedures. He froze 20 plastic straws, each containing about 8 million viable sperm. In addition to this deceased male, I have collected and cryopreserved semen from several living wild males for future use. </p>
<p>By testing thawed semen, our team has found that many of these sperm samples were capable of fertilizing cat eggs in vitro. The next step is figuring out whether the frozen wild ocelot semen really can produce kittens via artificial insemination. So Swanson packed up three frozen straws to ship to Albuquerque in a liquid nitrogen dry shipper tank to make sure they remain at -320 F (-196 C) throughout the journey.</p>
<h2>After the thaw, hoping for kittens</h2>
<p><a href="https://doi.org/10.1002/zoo.1010">Ocelots are induced ovulators</a>, meaning <a href="https://doi.org/10.1016/j.theriogenology.2006.03.011">a female must mate in order to release an egg</a> into her reproductive tract. The female we were working with was treated with hormones to help her ovulate at the proper time relative to the insemination procedure. The relief was overwhelming when we confirmed, by laparoscopically looking at the surface of the ovary, that the female had ovulated multiple eggs. </p>
<p>After thawing the semen straws, my excitement began to increase because we could see the deceased ocelot’s sperm swimming rapidly across a slide under the microscope. The sperm had survived the freezing and thawing process and was still in great shape.</p>
<p>I took multiple deep breaths to steady my hands as my smile spread from ear to ear. Bill Swanson positioned the insemination needle within each oviduct, I injected the sperm into both sides of the female’s reproductive tract, and the procedure was complete. </p>
<p>Unfortunately, although the female responded well to the ovulation synchronization protocol, and the artificial insemination procedure was performed without a hitch, she did not conceive. That’s not an uncommon outcome when <a href="https://doi.org/10.1016/S0378-4320(00)00099-3">using frozen semen</a>.</p>
<p>However, we are optimistic that future procedures – using semen samples from this specific male and other frozen samples from living, wild ocelots – will successfully produce pregnancies. By the end of 2021, we plan to conduct two additional artificial insemination procedures with zoo-managed ocelots, followed by three or four more in 2022.</p>
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<a href="https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="leashed ocelot stands atop cryo tanks" src="https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=772&fit=crop&dpr=1 600w, https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=772&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=772&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=970&fit=crop&dpr=1 754w, https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=970&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/431082/original/file-20211109-27-zdrke4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=970&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sihil the ocelot began life as a frozen embryo in one of these liquid nitrogen cold storage tanks. Kittens born via artificial insemination will be the next step.</span>
<span class="attribution"><span class="source">Tom Uhlman</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>If any of these artificial insemination procedures result in the birth of offspring, it will be the first time kittens have been produced with frozen semen from a wild ocelot. They’ll add greater diversity to the ocelot population managed in North American zoos, while improving our understanding of possibilities for increasing genetic diversity within wild ocelot populations. This success would help demonstrate the feasibility of producing kittens using frozen semen from the endangered Texas ocelot population.</p>
<p>Further refinement of the knowledge and techniques to create genetic exchange between wild and zoo-managed ocelot populations or among wild ocelot populations living in fragmented habitats will help ensure that these animals survive into the future.</p><img src="https://counter.theconversation.com/content/166397/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ashley Reeves is a PhD student within the University of Tennessee Comparative and Experimental Medicine Department and The Center for Wildlife Health. She receives funding from The University of Tennessee and The East Foundation. </span></em></p>There are so few wild ocelots in the US that the cats are becoming inbred, with a bad prognosis for their ultimate survival. But researchers are perfecting ways to get new genes into the population.Ashley Reeves, DVM, PhD Candidate in Comparative and Experimental Medicine, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1491742020-11-12T19:50:05Z2020-11-12T19:50:05ZFierce female moles have male-like hormones and genitals. We now know how this happens.<figure><img src="https://images.theconversation.com/files/368987/original/file-20201112-23-1ourijf.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C4000%2C2652&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>Moles live a tough life underground. As a result, they’ve evolved helpful adaptations, such as excavator-like claws. Female moles in particular have evolved an unusual strategy: high levels of the male hormone testosterone. </p>
<p>This is an evolutionary advantage. It produces stronger muscles for digging and foraging and aggression, to help mothers defend themselves and their young. </p>
<p>Most of the year, female moles look and behave like males. They have masculinised genitals, with no external vagina and an enlarged clitoris. But when mating season comes, testosterone levels drop and a vagina is formed; mating and birth follow.</p>
<p>How they accomplish this remained a mystery for a long time. But now, the <a href="https://science.sciencemag.org/content/370/6513/208.abstract">complete sequencing</a> of the mole genome has revealed the genetic tweaks underpinning this strange cycle in female moles, by which reproductive organs (gonads) develop and hormones are produced.</p>
<h2>Gonads and hormones</h2>
<p>Male development in humans and other mammals is determined by chromosomes (the structures within cells of living things that contain genes). Females have two copies of an X chromosome. Males have a single X and a male-specific Y chromosome. </p>
<p>In XY embryos, a gene called <em>SRY</em> on the Y chromosome intervenes in a network of another 60 genes. <em>SRY</em> turns on testis genes and turns off ovary genes to transform a ridge of cells into a testis. </p>
<p>In the testis, one cell type becomes specialised to make sperm and another (Leydig cells) makes male hormones, including testosterone. </p>
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Read more:
<a href="https://theconversation.com/what-makes-you-a-man-or-a-woman-geneticist-jenny-graves-explains-102983">What makes you a man or a woman? Geneticist Jenny Graves explains</a>
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<p>Testosterone is responsible for the most visible sex differences in males, such as bigger bodies, more muscle mass, male genitalia and more aggression. In XX embryos, an alternate pathway makes an ovary, which pumps out oestrogen.</p>
<p>So in mammals, different genetic pathways drive the same patch of embryonic tissue to become either an ovary or a testis. Generally, there’s no in-between. </p>
<p>But female moles have a patch of testis within their ovaries.</p>
<h2>An evolutionary balancing act</h2>
<p><a href="https://dev.biologists.org/content/118/4/1303">In 1993</a>, it was discovered the basis for “intersex development” in female moles is a gonad with both ovarian and testicular tissue. </p>
<p>Like other male mammals, male moles have a Y chromosome, bearing the <em>SRY</em> gene which directs testis formation. </p>
<p>Also like other mammals, female moles lack a Y chromosome. Curiously, however, instead of developing ovaries they develop “ovotestes”, with ovarian tissue at one end and testicular tissue at the other. </p>
<p>The ovarian tissue makes eggs and gets larger during breeding, then regresses. The testicular tissue is full of Leydig cells that make testosterone (but not sperm). Outside of breeding season, it expands until it’s larger than the ovarian end. </p>
<p>This explains why female moles have male-like genitalia, and are muscular and aggressive. But how does a patch of testis form in female moles if they have no <em>SRY</em> gene to trigger the process?</p>
<h2>Genetic tweaks behind ovotestis development</h2>
<p>To look for genetic changes that could allow this to happen, a global consortium of scientists <a href="https://science.sciencemag.org/content/370/6513/208.abstract">sequenced the entire mole genome</a>.</p>
<p>They found no differences between moles and other mammals in the protein products of the 60-odd genes involved in sex determination. However, they did discover mutations that altered the <em>regulation</em> of two of these genes in female moles.</p>
<p>One difference was found in the DNA sequences of a gene that’s vital for developing testes: <em>FGF9</em>. In all mammals, this gene switches on testis growth in XY embryos and inhibits genes that determine ovarian development. </p>
<p>In females of other mammals, the <em>FGF9</em> gene is turned off in the absence of <em>SRY</em>, but in female moles it stays on. </p>
<p>Genome sequencing revealed why: a big patch of DNA just upstream of <em>FGF9</em> is flipped around in moles. This inversion removes the usual control sequences from the gene, allowing it to stay on for longer in XX embryos.</p>
<p>The other gene impacted in female moles is <em>CYP17A1</em>, which codes for an enzyme that’s key to producing androgens (male hormones). In female moles, this gene and its surrounds have two extra copies, which increases testosterone output. </p>
<p>To show these genomic changes were indeed responsible for masculinising female moles, the researchers introduced them into mice, causing sex reversal and higher testosterone levels.</p>
<p>It’s important to note these evolutionary changes are in the <em>regulation</em> of gene activity, rather than in the regulation of protein products — which could compromise other normal functions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Clownfish (_Amphiprioninae_)." src="https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368997/original/file-20201112-19-gi6jel.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&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">Other than mammals, many marine animals have gender-bending tendencies. Clownfish always begin life as hermaphrodites carrying both female and male reproductive organs. Later in life, males can become female on an as-needed basis to mate with other males.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/szipiszopi/4919095469/in/photolist-8uFDGR-d6iqgf-2pEgAR-a3xGB7-4t985n-a3uQ4i-5cadh1-8ECGaX-3L8UN5-up9Mh-3L8UYN-Cu66xD-9pfPTN-8GLsLd-4kL2uD-4J1u8d-8FsdQs-dzruc-5DpDBY-5GUkSb-4kQ5YW-4kL38D-8WkdZn-KozKd7-qnrwnJ-coksCs-a6fGi2-2wMpjF-FPVyZy-38dWFC-PGX7c4-Kc29n9-gRkLPn-xDeEWy-EjqyJJ-6Y189v-rGsD6c-34WhVy-6YA5ez-gRkSs5-4g9oXn-pjBqbJ-6XX1Zc-nfKMRT-4kL1Ke-4J1sGC-5j4jKU-5LYxz4-aad1RH-ayLz3G">Istvan/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
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Read more:
<a href="https://theconversation.com/what-we-learn-from-a-fish-that-can-change-sex-in-just-10-days-129063">What we learn from a fish that can change sex in just 10 days</a>
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<h2>What this means for sex and evolution</h2>
<p>Since mammals, including humans, develop as either males or females, we’ve been accustomed to regard testis or ovary development in the embryo as strict alternatives, depending on an on/off switch (the presence or absence of the Y chromosome and <em>SRY</em> gene). </p>
<p>But we now know there’s a complex gene network full of checks and balances that is the basis for alternate pathways of sexual development.</p>
<p>There are many studies of human babies born with <a href="http://theconversation.com/boy-girl-or-dilemmas-when-sex-development-goes-awry-49359">mutations in one of these genes</a>. This points to a more complex picture of the wiring behind the “switch” responsible for variation in human sexual development. </p>
<p>There are fierce females in other mammal species, too. Female spotted hyenas are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0018506X00916349">bigger and more dominant</a> than males and have male-like genitalia. We don’t know how this change works at a genetic level. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A female spotted hyena in the wold." src="https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368992/original/file-20201112-17-1axmrqx.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>
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<span class="caption">The spotted hyena, <em>Crocuta crocuta</em> (also known as the ‘laughing hyena’) is native to sub-Saharan Africa. In females such as this one, the clitoris is shaped and positioned like a penis that can become erect.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>The downside of this is that mating is tricky. Cubs are birthed through the female’s narrow phallus. Mothers and/or cubs often die during this fraught process.</p>
<p>So while these larger, more aggressive females rule the hyena roost and get first pick at meals, like most things in nature, it seems this comes at a price.</p>
<p>Big fierce female moles and hyenas remind us the natural world, as always, features unique evolutionary differences — enlightening our view on human variation.</p><img src="https://counter.theconversation.com/content/149174/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jenny Graves receives funding from the Australian research Council. </span></em></p>Female moles evolved to have high testosterone levels, making them fiercer diggers and mothers. Female hyenas share this trait, but it means they must give birth through a male-like phallus.Jenny Graves, Distinguished Professor of Genetics and Vice Chancellor's Fellow, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/966352019-05-20T04:03:42Z2019-05-20T04:03:42ZManaging mutations of a species: the evolution of dog breeding<figure><img src="https://images.theconversation.com/files/259476/original/file-20190218-56220-1789by1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Wire Fox Terrier named King is trotted out before being named Best in Show on the second night of the 2019 Westminster Kennel Club Dog Show.</span> <span class="attribution"><span class="source">JUSTIN LANE/EPA</span></span></figcaption></figure><p>In the first edition of <a href="http://darwin-online.org.uk/EditorialIntroductions/Freeman_OntheOriginofSpecies.html">On the Origin of Species</a>, Charles Darwin mentions dogs 54 times. He does so mainly because the extraordinary variation between dog breeds provides a marvellous illustration of the power of selection. For most of the roughly 15,000 years since their domestication, dogs were selected by humans for their usefulness as hunters, retrievers, herders, guards or companions. </p>
<p>As modern breeds became recognisable, the extent to which a dog aligned with the expected shape, size and coat for its breed (known as “conformation”) became more important. So important, in fact, that just a few years before On the Origin of Species hit the bookshops, the world’s first conformation-based dog show was held in the Town Hall of Newcastle-upon-Tyne in England.</p>
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<a href="https://theconversation.com/is-your-dog-happy-ten-common-misconceptions-about-dog-behaviour-97541">Is your dog happy? Ten common misconceptions about dog behaviour</a>
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<p>By 1873, the UK <a href="https://www.thekennelclub.org.uk/our-resources/about-the-kennel-club/history-of-the-kennel-club/">Kennel Club</a> was formed to, among other things, regulate the showing and breeding of dogs. Similar organisations soon followed in other countries. The criteria for judging and breeding for conformation were formalised in breed standards that are now administered by kennel clubs around the world. </p>
<p>Unfortunately, breeding for the standard in some breeds resulted in <a href="https://theconversation.com/vets-can-do-more-to-reduce-the-suffering-of-flat-faced-dog-breeds-110702">serious compromises to health and welfare</a>, especially in cases where the wording of the standard encouraged exaggeration of certain features. </p>
<h2>Breeds to watch out for</h2>
<p>The Kennel Club <a href="https://www.thekennelclub.org.uk/services/public/breed/watch/Default.aspx">Breed Watch</a> has highlighted roughly 15% of breeds as having “breed-specific conformational issues which may lead to health problems” and a further 4% of breeds in which “some dogs have visible conditions or exaggerations that can cause pain or discomfort”.</p>
<p>Fortunately, there is now global coordination in addressing these issues. The <a href="https://dogwellnet.com/">International Partnership For Dogs (IPFD)</a> which works with many of the world’s leading breed-regulating organisations, is highlighting “<a href="https://dogwellnet.com/content/international-actions/extremes-of-conformation-brachycephalics/extremes-of-conformation-dwn-resources-r569/">extremes of conformation</a>”.</p>
<p>Without up-to-date prevalence data on each disorder, we cannot be sure how effective watch lists or changes in breed standards have been in tackling these disorders. Furthermore, in 2009-2010, one of us (Paul McGreevy) helped to show that while <a href="https://www.ncbi.nlm.nih.gov/pubmed/19836981">some of the conformational issues of concern are related to breed standards</a>, others are <a href="https://www.ncbi.nlm.nih.gov/pubmed/19963415">inherited disorders not related to breed standards</a>. </p>
<p>So, even if there were no breed standards and dogs were bred solely for health and welfare, many inherited disorders would still occur. In fact, the vast majority of inherited disorders have nothing to do with conformation.</p>
<p>All inherited disorders (and all desirable inherited traits) are, in essence, the result of random mutations in DNA that have occurred and continue to occur in all species.</p>
<p>The number of known inherited disorders varies enormously among species, mainly reflecting the extent of research effort. For example, the number of single-gene disorders documented in humans is <a href="https://www.omim.org/statistics/geneMap">more than 5,300</a>, whereas the figure for dogs is <a href="https://omia.org">fewer than 300</a>. As many of the inherited disorders that occur in humans could also occur in dogs, the present number for dogs is likely to be just the tip of the iceberg. </p>
<p>A global research effort is providing an ever-increasing number of DNA tests for known canine inherited disorders, enabling (in many cases) elimination of the disorder. National kennel clubs provide <a href="https://www.thekennelclub.org.uk/health/for-breeders/dna-testing-simple-inherited-disorders/worldwide-dna-tests/">useful guidance on testing</a> and <a href="https://www.thekennelclub.org.uk/services/public/mateselect/test/Default.aspx">public access to test results on individual dogs</a>. The IPFD provides global information for breeders on the <a href="https://dogwellnet.com/ctp/">harmonisation of genetic testing for inherited disorders in dogs</a>. </p>
<p>One of us, Paul McGreevy, has been part of an international team that developed a <a href="https://www.ncbi.nlm.nih.gov/pubmed/21742521">risk-assessment criterion</a> for determining priorities for research and control of inherited disorders. A major component of this score is the prevalence of a disorder in a particular breed.</p>
<h2>Estimating the prevalence of disorders</h2>
<p>Fortunately, digital health has arrived in the veterinary sphere and is set to provide, for the first time, comprehensive estimates of disorder prevalence. </p>
<p>Paul is the chair of <a href="http://www.mdpi.com/2076-2615/7/10/74">VetCompass Australia</a>, based on the highly successful <a href="https://www.rvc.ac.uk/vetcompass">UK VetCompass</a> that he helped to establish ten years ago. It’s the first Australia-wide surveillance system that gathers together clinical records on companion animal diseases and treatments. </p>
<p>Bringing together all seven Australian veterinary schools, VetCompass Australia collects clinical records from hundreds of vets across the country for researchers to interrogate. Analysis of these records will reveal trends in the prevalence of inherited and acquired diseases, identify effective treatments, and help vets and breeders improve dogs’ quality of life.</p>
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Read more:
<a href="https://theconversation.com/vets-can-do-more-to-reduce-the-suffering-of-flat-faced-dog-breeds-110702">Vets can do more to reduce the suffering of flat-faced dog breeds</a>
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<p>The vision for this surveillance system is that it will one day provide real-time data on the prevalence of each known disorder and show how effective various control strategies are. Real-time data will also sound the alarm on clusters of new disorders as they emerge.</p>
<p>Complementing VetCompass is <a href="http://www.mybreeddata.com/crm/index.html">MyBreedData</a>, a Finland-based website that collects the results of genetic analyses from huge numbers of dogs to identify mutations known to cause particular inherited disorders. Among other things, this information provides early warning signs of which breeds contain which harmful mutations. </p>
<h2>What about hybrid vigour?</h2>
<p>Hybrid vigour for a particular trait is the extent to which, on average, the puppies from the mating of a purebred female from one breed with a purebred male from another breed, are better for that trait than the average of the two parental breeds for that trait.</p>
<p>Evidence from other species suggests that hybrid vigour in dogs could occur to a limited extent in traits related to health, welfare, and fitness for purpose. The greater the genetic difference between two breeds, the greater the hybrid vigour is expected to be in first-generation offspring between those breeds. </p>
<p>Specifically, first-generation offspring are unlikely to develop any recessive disorders that are present in only one of the two parental breeds. On the other hand, they can obviously develop inherited disorders that are present in both parental breeds, which is often the case for disorders such as hip dysplasia. </p>
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<a href="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=487&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=487&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=487&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=612&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=612&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=612&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">Husky dog waiting for his turn to be judged at a dog show in Bishkek, Kyrgyzstan, 05 May 2019. The International Kennel Club Dog Show was held in Bishkek.</span>
<span class="attribution"><span class="source">EPA/IGOR KOVALENKO</span></span>
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<p>Importantly, breeding beyond first-generation crosses reduces hybrid vigour and unleashes unpredictable variation. This is good news for traditional stud breeders, because it means the most desirable hybrids are the offspring of two purebreds, rather than those bred subsequently.</p>
<p>Mixed-breed (or “designer”) dogs are not new: the Kennel Club has been <a href="https://www.thekennelclub.org.uk/getting-a-dog-or-puppy/finding-the-right-dog/crossbreed-dogs/">registering them for more than 50 years</a>. Unfortunately, most peer-reviewed studies of canine cross-breeds do not let us estimate actual hybrid vigour, simply because they fail to report the parentage of mixed-breed dogs. </p>
<p>Fortunately, obtaining evidence of actual hybrid vigour in dogs <a href="https://www.ncbi.nlm.nih.gov/pubmed/27387730">should be relatively straightforward</a>: it simply requires veterinary records to include the parentage of mixed-breed dogs, when known. </p>
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Read more:
<a href="https://theconversation.com/are-you-walking-your-dog-enough-100530">Are you walking your dog enough?</a>
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<p>The information being collected by VetCompass and MyBreedData will provide a firm foundation for prioritising research into, and schemes for controlling, inherited disorders within breeds. It also has potential to shed valuable light on the extent to which hybrid vigour exists in dogs. Armed with this information, breeders will be able to combine new technology with the skills of traditional dog breeding to breed dogs that are more likely to look great, be healthy and thrive in the niches we provide for them.</p><img src="https://counter.theconversation.com/content/96635/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul McGreevy consults on a voluntary basis to the RSPCA Australia and is a lifetime member of the RSPCA NSW. He receives funding from the Australian Research Council. In 2017, he received an International Lifetime Achievement Award from the UK Kennel Club.</span></em></p><p class="fine-print"><em><span>Bethany Wilson consults to RSPCA Australia on an ad hoc basis.</span></em></p><p class="fine-print"><em><span>Frank Nicholas 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 global research effort is targeting inherited disorders in dogs.Paul McGreevy, Professor of Animal Behaviour and Animal Welfare Science, University of SydneyBethany Wilson, Honorary Affiliate, University of SydneyFrank Nicholas, Emeritus Professor of Animal Genetics, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/642542016-08-31T13:15:41Z2016-08-31T13:15:41ZGenetic studies may hold the key to saving west and central Africa’s lions<figure><img src="https://images.theconversation.com/files/135928/original/image-20160830-28244-1190wuj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">African lions were all considered to belong to a single subspecies but new research refutes that.</span> <span class="attribution"><span class="source">Laura Bertola</span></span></figcaption></figure><p>Tropical rain forests, dry deserts and mountainous vistas: Africa is home to all of these very different ecosystems and more. Its varied ecosystems provide a habitat for numerous species, and the continent harbours a great richness of biodiversity.</p>
<p>But within species, there is another level of biodiversity: genetic variation. Even within species, there are wildly different populations. These are studied in the growing field of <a href="http://tolweb.org/treehouses/?treehouse_id=4383">phylogeography</a>. This science explores the distribution of genetic diversity, or the extent of different genetic lineages, in the context of geography. The formation of mountain ranges or islands, or the extension of rivers or forests, all influence the distribution of species: from trees, to tiny flying insects – to top predators like the lion. </p>
<p>Understanding species at this level is vitally important in the fight against extinction. Genetic diversity includes the evolutionary potential, referring to the genetic blue print that allows a species to adjust to a changing environment. If genetic diversity is lost, for example, when unique genetic lineages go extinct, it means that the species loses part of its adaptability. This makes species more vulnerable to extinction.</p>
<h2>New research paints a different picture of the lion</h2>
<p>Earlier <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137975">research</a> has shown that lions in west and central Africa deviate from their counterparts in east and southern Africa. This, despite the fact that all African lions are considered to belong to a single subspecies. </p>
<p>In a new <a href="http://www.nature.com/articles/srep30807">publication</a>, a new magnitude of data was gathered analysing lion populations from 22 countries. This data set includes samples from each confirmed lion population in west and central Africa. This region is particularly important because lions and other wildlife are declining. As a result, it is a major concern for conservation <a href="http://news.nationalgeographic.com/news/2014/01/140108-west-african-lions-endangered-conservation-science/">projects</a>.</p>
<p>The data helped discern six lineages in the lion. These can be divided into two major groups:</p>
<ol>
<li><p>A northern group, containing lions from west Africa, central Africa and the Asiatic subspecies.</p></li>
<li><p>A southern group, containing lions from north east Africa, east/southern Africa and south west Africa. </p></li>
</ol>
<p>Based on genetic data it was also possible to calculate the timing of this split, based on the notion that differences in the DNA accumulate over time. It was estimated that the major split may have occurred around 300,000 years ago. This estimate allows us to explore further what happened during this period which could explain the differentiation between these two groups of lions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.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">New research shows the differentiation in lion genetics came about from the expansion of African rain forests around 300,000 years ago.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Reasons for differentiation</h2>
<p>The researchers suggest that during this period the African rain forest expanded and probably formed a barrier for lion dispersal. Cyclical expansion of rain forest on one side and dry desert on the other side may have pushed lion populations into isolated pockets of suitable habitat. And this led to the genetic differentiation we still see today. </p>
<p>Another <a href="https://www.researchgate.net/publication/235635309_Climate_envelope_models_suggest_spatio-temporal_co-occurrence_of_refugia_of_African_birds_and_mammals">study</a>, which used habitat suitability models for mammal and bird species, predicted six regions that maintained a suitable habitat during historic periods of climate change. These six regions correspond directly with the six genetic lineages found in the lion. This suggests that the high resolution phylogeographic pattern found in the lion is illustrative for a range of species. </p>
<p>Since these climatic changes didn’t just act on the lion. A large variety of species like giraffe, buffalo, cheetah and spotted hyena were also affected. The recent publication used the case of the lion to compare it to available data sets of other Savannah mammals. It showed that a large number of species have a similar pattern in which populations from west and central Africa deviated from populations in east and southern Africa. </p>
<p>This is an important finding because it shows that we will lose important and unique biodiversity if we fail to preserve the populations in this region.</p>
<h2>Challenging times</h2>
<p>In July a delegation of the west and central African lion conservation network, <a href="http://www.rocal-lion.org/">ROCAL</a>, travelled to Botswana to explore opportunities for <a href="http://leofoundation.org/en/study-trip-to-botswana/">collaboration</a>. There are large differences between parts of west/central Africa and parts of east/southern Africa in terms of ecology, politics and their socioeconomic situations. These differences present many challenges. But they are also a source of opportunities for west and central African countries to market their unique situation, both in terms of natural and cultural diversity.</p>
<p>In addition, during the <a href="http://www.iucnworldconservationcongress.org/">IUCN World Conservation Congress</a> in September 2016, a delegation of researchers who were also involved in the publication will propose to set up a Species Action Partnership for west and central Africa. The hope is that this will facilitate coordination and funding of projects in the region.</p>
<p>Phylogeographic data sets show why it’s necessary to move beyond the idea merely of preserving a species. Genetic data can be used to develop a conservation plan that incorporates the full scope of biodiversity. Failure to do so could see the African continent lose a unique part of its richness in the next few decades.</p><img src="https://counter.theconversation.com/content/64254/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Bertola 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>African lions were initially thought to belong to a single subspecies but new research shows that there is more diversity on the African continent.Laura Bertola, Researcher in Conservation Genetics, Phylogeny/Phylogeography, Population Genetics/Genomics and Environmental DNA, Leiden UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/578252016-07-19T16:26:58Z2016-07-19T16:26:58ZWho took red deer to the Scottish isles?<figure><img src="https://images.theconversation.com/files/128032/original/image-20160624-28373-5z965e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The majestic, wild red deer.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-233719480/stock-photo-red-deer-in-mating-season.html?src=ingmGFsJf2OMkYeLBd5Y0A-1-0">Shutterstock/Menno Schaefer</a></span></figcaption></figure><p>Red deer are the largest surviving native land mammals in the British Isles. Over the centuries, wolves, bears, elk and wild cattle have all been driven to extinction, but deer have persisted. Though they are now limited to the margins of the modern world, in the past these animals played a central role in human life and, somehow, unlike other large mammals, endured. </p>
<p>It is easy to understand how deer arrived at some of the remote places on the British mainland where they now thrive, but questions arise over how the animals on the distant Scottish islands of Orkney and the Outer Hebrides got there. Deer are known to be good short distance swimmers, but the isles are thought to have been separated by wide and deep sea channels from the mainland for as long as Britain itself has been an island. Today, other than deliberate introductions, these outer isles still have only a few terrestrial species, such as otters and rodents.</p>
<p>The archaeological record shows that deer appeared on the Scottish isles at the same time as humans arrived, so could there be a link between the two? Evidence for the first insular human and deer populations on these islands dates back to the Neolithic, some 5,500 years ago, a time when the first farmers were <a href="http://www.bbc.co.uk/history/ancient/british_prehistory/overview_british_prehistory_01.shtml#one">establishing themselves</a> in Britain. These farmers <a href="http://ngm.nationalgeographic.com/2014/08/neolithic-orkney/smith-text">spread across to the islands</a>, taking with them domestic cattle, sheep, pigs and crops, as well as wild deer. By releasing the deer, settlers developed a new, less labour intensive food supply that could supplement farming, and provide valuable antler – but just how did they do it?</p>
<h2>Deer movement</h2>
<p>In our recent study, we combined archaeological skills <a href="https://www.researchgate.net/publication/299840919_Colonization_of_the_Scottish_islands_via_long-distance_Neolithic_transport_of_red_deer_Cervus_elaphus">with genetic research</a>, to understand how our ancestors moved deer to and from the islands. The results were unexpected.</p>
<p>We attempted to match DNA sequences from ancient deer bones found across Scotland from different times, with the populations of deer living on other nearby places, such as the Scottish mainland, Norway and Ireland. By including deer from the Bronze, Iron and Viking Ages we also explored if they were introduced to the islands once or many times.</p>
<p>Though we found that deer from mainland Scotland and the Inner Hebrides were all close matches with the Irish and Norwegian deer, only a single specimen of ancient deer from the outer isles matched any deer population, modern or ancient. These animals actually came from much further afield – but from where did they originate?</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IEssrQajHWw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>There are some other enigmatic island introductions we can compare the deer to. <a href="http://onlinelibrary.wiley.com/doi/10.1111/mec.12462/abstract">One study</a> suggested that the Orkney vole, a species only found on mainland Europe and on Orkney, which also appears at the time of the first farmers, most closely <a href="http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-23942934">matches historic voles in Belgium</a>. Research is also shedding new light on our understanding of the movement of early people as well as their relationships with wild animals. While sea-going prehistoric boats are rare in Britain, there is <a href="http://www.sciencedirect.com/science/article/pii/S0305440306001804">increasing evidence</a> that people travelled and traded over long distances, so it could be that they came from even further afield than first thought.</p>
<h2>Harmonious living</h2>
<p>The deliberate introduction of deer to the islands suggests that early farmers diversified, employing a sophisticated land and stock management system. The deer provided meat, fat, hides and sinews, while antler, shed and regrown each year, was a vital sustainable resource used to make tools and other items. Bones left by islanders suggest that, in the absence of predators, ancient deer numbers were managed by culling the young animals. This close management allowed humans and deer to both persist on the small islands for centuries, and provides a model for our understanding of how and why deer, unlike other large mammals, were not hunted to extinction.</p>
<p>Today, deer are big business. Britain is home to some 350,000, the largest population in Europe, and deer stalking is estimated to be worth over <a href="http://www.bbc.co.uk/news/uk-scotland-highlands-islands-20875307">£100m a year to the Scottish economy</a>. However, the animals no longer have any natural predators and conservationists are worried that their huge numbers are damaging the natural environment, forestry and agriculture, as well as compromising road safety.</p>
<p>As these remote deer populations are still managed by humans, and their genetic line remains <a href="http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/7842458.stm">free from interbreeding</a>, we can ensure the ancient deer lineages are protected. And by comparing modern deer with their ancestors, we can conserve and manage our herds today to ensure their continued survival in the future. But the search for the source of the original Scottish island deer continues. We will now be looking further afield for the source populations and testing ancient and modern deer across southern Britain and into Europe. In particular, whether there is a link with the Orkney vole.</p>
<p>Questions are still outstanding, however: where did these mysterious island deer come from? What does this tell us about the people that they lived alongside? And what other mysteries are there still to discover about this ancient human wildlife relationship?</p><img src="https://counter.theconversation.com/content/57825/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Our funding for this project was not external (it was from within Cardiff University), but it was building on material collected as part of a NERC project NE/FO21541.</span></em></p><p class="fine-print"><em><span>David Stanton and Mike Bruford do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Red deer on the Scottish isles have the same DNA as their ancient ancestors – scientists are now uncovering how they got there in the first place.David Stanton, Research associate, Cardiff UniversityJacqui Mulville, Reader in Bioarchaeology, Cardiff UniversityMike Bruford, Professor of Organisms and Environment, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/500822015-11-23T04:37:29Z2015-11-23T04:37:29ZHow translocating rhinos promotes genetic health and keeps them safe<figure><img src="https://images.theconversation.com/files/100901/original/image-20151105-16263-8dszck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The translocation of rhinos can help conservation and build their populations. </span> <span class="attribution"><span class="source">Nikki le Roex</span></span></figcaption></figure><p>Rhino poaching is one of the largest threats of the illegal wildlife trade. The animals are slaughtered for their horns, believed in some Asian cultures to have <a href="http://www.rhinosinfo.com/rhino-horn-as-medicine.html">medicinal properties</a>. Rhino populations across southern Africa are being decimated. As of August 27, 2015, 749 rhinos had been <a href="https://www.environment.gov.za/mediarelease/molewa_highlightsprogress_onrhinopoaching">killed</a> in eight months in South Africa alone.</p>
<p>One of the interventions that is being increasingly pursued is to translocate the animals. Across Africa rhinos are being <a href="http://www.sanparks.co.za/about/news/?id=56244">translocated</a> from national parks to private strongholds. Regular rhino translocations take place in South Africa and Namibia. Some rhino are moved annually in Zimbabwe, Kenya and Botswana, which have smaller populations.</p>
<p>South Africa has by far the largest rhino population in the world and does the most translocations globally. Both <a href="http://www.wwf.org.za/what_we_do/rhino_programme/black_rhino/">black</a> and white rhino have been translocated in previous years to establish new populations and grow existing groups. </p>
<p>In 2014, more than <a href="https://www.environment.gov.za/mediarelease/molewa_waragainstpoaching2015">150 rhino</a> were translocated by government and private initiatives. This is an active conservation strategy designed to protect the remaining animals, cut down on those lost to poaching and ensure the health and growth of future rhino populations. </p>
<p>Translocations typically take place in the drier and cooler months of the year. Rhino are darted from a helicopter. Blood and tissue samples are taken once the animal is immobilised. These samples can be used in <a href="http://www.up.ac.za/en/faculty-of-veterinary-science/news/post_1951095-up-initiative-leads-in-rhino-poaching-prosecution">poaching cases</a> and for scientific research. The rhino is then walked into a crate and lifted by crane onto a flatbed truck to be transported to a new location. </p>
<h2>The where and the why</h2>
<p>Wildlife translocations can supplement small populations, replace animals that are lost to poaching or disease and re-introduce species into their former range. As most wildlife populations are now restricted to fenced parks and reserves, animals can no longer move into vacant areas on their own or disperse between populations for new breeding opportunities.</p>
<p>In the past, animals could also avoid dangerous areas, or leave a population that had become too large to be supported in that environment. As this can no longer happen naturally, park managers must ensure that the necessary movement of animals takes place.</p>
<p>The most obvious benefit to translocating rhino is protection from poachers. The sheer size of the larger game reserves make rhino vulnerable to poachers. Such extensive boundaries cannot be permanently policed. </p>
<p>Small reserves can be more thoroughly protected by rangers or private security. Movements within parks from high poaching zones to more heavily monitored <a href="http://www.sanparks.org/about/news/?id=56382">protection zones</a> can also give rhino a better chance of survival.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/102370/original/image-20151118-14207-1ls03b0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rhino translocations typically happen during the dry months.</span>
<span class="attribution"><span class="source">Nikki le Roex</span></span>
</figcaption>
</figure>
<h2>Moving animals promotes genetic health</h2>
<p>Translocations can also be used as a conservation tool to increase the genetic health of a population and prevent inbreeding. This is particularly important in small populations. Genetics is a hugely important aspect to consider when translocating animals. Failure to do this can have <a href="https://theconversation.com/why-moving-south-african-lions-to-rwanda-is-not-without-problems-46273">serious impacts</a> on the animals.</p>
<p><a href="http://www.wwf.org.au/our_work/saving_the_natural_world/what_is_biodiversity/genetic_diversity/">Genetic diversity</a> is a measure of a populations’ genetic health. It represents the number of <a href="http://labs.biology.ucsd.edu/woodruff/pubs/194.pdf">differences</a> between the genetic code of individuals, which may enable the animals to cope better with disease or other environmental pressures. Large populations usually have a higher genetic diversity compared to small isolated populations. Small populations may have less variation and be more vulnerable to changing conditions.</p>
<p><a href="http://evolution.berkeley.edu/evolibrary/article/conservation_03">Inbreeding</a> happens when populations become too small and related animals are forced to breed with each other. This might not have an immediately negative impact, but may severely compromise the health and reproduction of future generations. This is known as <a href="http://evolution.berkeley.edu/evolibrary/article/conservation_03">inbreeding depression</a>, and can put the survival and health of the whole population at risk in the long term.</p>
<p>Moving rhino from the Kruger National Park, which hosts the <a href="http://www.krugerpark.co.za/krugerpark-times-3-11-annual-census-23008.html">largest white rhino population</a> in South Africa, takes new genes and diversity to other locations. Other populations in southern Africa have been isolated for some time and this will be an excellent way to re-introduce gene variants that were lost when small rhino populations were founded from just a few individual animals.</p>
<h2>Long term commitment</h2>
<p>Rhinos live for a long time. They can reach up to 40 years of <a href="http://www.rhinoresourcecenter.com/species/black-rhino/">age</a>. This means that the removal of any single animal has a much greater impact. It isn’t just the individual animal that is lost, but all the offspring that would have been possible in the future. </p>
<p>This is particularly true for females of breeding age. These breeding females are essential for raising calves and the survival of the population. Increasing the number of females also promotes maximum growth in a population.</p>
<p>The planned movement and sale of rhino allows additional safeguards. Conditions can be included into purchase contracts to ensure that the benefits of translocation are maximised. For example, a commitment to breed the rhino as soon as they are introduced to their new environment ensures the population growth. Clauses that prevent hunting the translocated animals for a pre-determined time period also safeguard the animals for the future.</p>
<p>The <a href="http://www.sanparks.org/about/news/?id=56244">South African National Parks</a> rhino capture teams are extremely experienced with rhino capture and translocation. This commitment from conservation managers as well as governments and NGOs is vital for protection from poaching and to ensure the genetic health and growth of future rhino populations. </p>
<hr>
<p><em>This article was written in collaboration with Dr Markus Hofmeyr, the head of Veterinary Wildlife Services at South African National Parks.</em></p><img src="https://counter.theconversation.com/content/50082/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nikki le Roex 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>Conservationists are increasingly looking to translocating rhinos. This not only ensures their safety but also enables improvements to their genetic health.Nikki le Roex, Postdoctoral Fellow in Wildlife Genetics, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.