tag:theconversation.com,2011:/fr/topics/out-of-africa-22765/articlesOut of Africa – The Conversation2023-10-04T19:05:09Ztag:theconversation.com,2011:article/2147192023-10-04T19:05:09Z2023-10-04T19:05:09ZNew path for early human migrations through a once-lush Arabia contradicts a single ‘out of Africa’ origin<figure><img src="https://images.theconversation.com/files/551581/original/file-20231002-21-9nvrqz.JPG?ixlib=rb-1.1.0&rect=0%2C10%2C3456%2C2286&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A general view of Wadi Gharandal riverine wetland, along the Jordan Rift Valley, showing palm trees concentrated at the centre of the wadi near the active spring.</span> <span class="attribution"><span class="source">Mahmoud Abbas</span></span></figcaption></figure><p>Our species, <em>Homo sapiens</em>, migrated out of Africa multiple times – reaching the Levant and Arabia between 130,000 and 70,000 years ago, as exemplified by human fossils and archaeological sites found at various locations. </p>
<p>Little is known, however, about the pathways of these migrations. In a <a href="https://doi.org/10.1126/sciadv.adi6838">study</a> published today in Science Advances, we find the now inhospitable and hyper-arid zone of the southern Jordan Rift Valley was frequently lush and well-watered in the past. </p>
<p>Our evidence suggests this valley had a riverine and wetland zone that would have provided ideal passage for hunter-gatherers as they moved out of Africa and deep into the Levant and Arabia.</p>
<h2>Wandering out of Africa</h2>
<p>Researchers hypothesise humans migrating <a href="https://www.sciencedirect.com/science/article/pii/S0277379116301494">out of Africa</a> would have used platforms in the eastern Sahara, the Nile River Valley, or the margins of the western Red Sea. </p>
<p>From there, these small bands of hunter-gatherers would have passed into the Sinai – a land bridge connecting Africa with the rest of Asia – following migrating animals and hunting a variety of them for sustenance. </p>
<p>For many of these hunter-gatherers, the next stop on the journey would have been the southern portion of the Jordan Rift Valley. This valley is situated in a strategic zone, with the Dead Sea to the north and the Gulf of Aqaba in the south. </p>
<p>Our field work was concentrated on three sites. The first two were <a href="https://www.researchgate.net/publication/344122987_A_wetland_oasis_at_Wadi_Gharandal_spanning_125-70_ka_on_the_human_migration_trail_in_southern_Jordan">Wadi Gharandal</a> and an area near the village of Gregra – both in the valley itself. The third site, <a href="https://livinginjordanasexpat.com/2019/08/21/hiking-wadi-al-hasa-%D9%88%D8%A7%D8%AF%D9%8A-%D8%A7%D9%84%D8%AD%D8%B3%D8%A7/">Wadi Hasa</a>, is located in the more elevated areas of the Jordan plateau. </p>
<p>“Wadi” is an Arabic word describing a temporary riverbed that only contains water during heavy rains.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=550&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=550&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=550&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=691&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=691&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551922/original/file-20231003-21-di5gym.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=691&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">We researched three sites, including two wadis and an area near a village called Gregra.</span>
<span class="attribution"><span class="source">Mahmoud Abbas</span></span>
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</figure>
<h2>When Arabia was a verdant land</h2>
<p>Our goal was to reconstruct the region’s past environmental settings by accurately dating various sections of sediment. We used a technique called luminescence dating to estimate how long sediment grains had been shielded from sunlight, thereby allowing us to calculate how old they were.</p>
<p>Our findings from sedimentary sections ranging 5 to 12 metres in thickness showed ecosystem fluctuations over time, including cycles of dry and humid environments. We also found evidence for the presence of ancient rivers and wetlands.</p>
<p>Luminescence dating showed the sedimentary environments formed between 125,000 and 43,000 years ago, suggesting there had been multiple wet intervals.</p>
<p>At Wadi Gharandal, our team recovered three stone tools associated with a wetland environment. Two of these were made using the <a href="https://link.springer.com/referenceworkentry/10.1007/978-3-319-47829-6_391-1">Levallois method</a> – a characteristic manufacturing technique known to have been used by both Neanderthals and <em>Homo sapiens</em>. We dated the tools to 84,000 years ago. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551928/original/file-20231004-29-i2gfqe.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">We collected samples for luminescence dating from the Wadi Hasa area in West Jordan. Pictured are Mahmoud Abbas, Mohammed Alqudah and Yuansen Lai.</span>
<span class="attribution"><span class="source">Zhongping Lai/Shantou University</span></span>
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</figure>
<p>Collectively, our fieldwork in the Jordan Rift Valley demonstrates the valley once functioned as a 360-kilometre-long freshwater corridor that helped funnel humans northward into Western Asia and southward into the Arabian Peninsula. </p>
<p>Further evidence for a northward expansion comes from the famous <a href="https://en.wikipedia.org/wiki/Skhul_and_Qafzeh_hominins">Skhul and Qafzeh</a> cave sites in Israel. Fossils of <em>Homo sapiens</em> and Levallois stone tools have been found here. </p>
<p>Towards the south, <a href="https://www.nature.com/articles/s41586-021-03863-;y">fieldwork</a> in northern Saudi Arabia has also demonstrated a network of rivers and lakes was once present in the region. This allowed humans to penetrate a green Nefud Desert replete with savannahs and grassland.</p>
<p>In the heart of the Nefud, the lakeside site of Al Wusta has produced a <a href="https://theconversation.com/our-fossil-finger-discovery-points-to-earlier-human-migration-in-arabia-94670">human fossil and Levallois stone tools</a> dating to 85,000 years ago. These dates coincide with the 84,000-year-old Levallois stone tools found at Wadi Gharandal. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/major-new-research-claims-smaller-brained-homo-naledi-made-rock-art-and-buried-the-dead-but-the-evidence-is-lacking-207000">Major new research claims smaller-brained _Homo naledi_ made rock art and buried the dead. But the evidence is lacking</a>
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<h2>Multiple migrations into South-West Asia</h2>
<p>Our findings from the Jordan Rift Valley indicate there were multiple early human migrations from Africa, and into Asia, during favourable conditions. This opposes the <a href="https://www.science.org/content/article/almost-all-living-people-outside-africa-trace-back-single-migration-more-50000-years">theory of a single</a>, rapid wave of human movement out of Africa <a href="https://education.nationalgeographic.org/resource/global-human-journey/">60,000 years ago</a>. </p>
<p>Our results also suggest, together with the Levantine and Arabian evidence, that hunter-gatherers used inland river and wetland systems as they crossed South-West Asia. This contradicts a popular model <a href="https://www.newscientist.com/article/mg18625005-200-humans-took-the-scenic-route-out-of-africa/">suggesting they mainly used</a> coastal routes as super-highways.</p>
<p>Although ancient DNA evidence indicates <em>Homo sapiens</em> interbred with Neanderthals and Denisovans multiple times as they spread into Asia, on-the-ground evidence for these encounters has generally been lacking. Our findings provide further evidence this area served as the ground for these encounters.</p>
<p>Yet numerous questions remain unanswered. Large swathes of territory in South-West Asia have not yet been surveyed or dated – and few fossils of our <a href="https://www.science.org/doi/abs/10.1126/science.aai9067">ancestors have been found</a> to shore up arguments about how early humans really dispersed.</p>
<p>We’ll need to closely investigate more long-neglected areas such as the Jordan Rift Valley to accurately portray how humankind’s voyage out of Africa unfolded. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/research-reveals-humans-ventured-out-of-africa-repeatedly-as-early-as-400-000-years-ago-to-visit-the-rolling-grasslands-of-arabia-167050">Research reveals humans ventured out of Africa repeatedly as early as 400,000 years ago, to visit the rolling grasslands of Arabia</a>
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<img src="https://counter.theconversation.com/content/214719/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zhongping Lai receives funding from the China Natural Science Foundation.</span></em></p><p class="fine-print"><em><span>Mahmoud Abbas and Michael Petraglia 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>The findings reveal a close association between climatic conditions and early human migrations out of Africa.Michael Petraglia, Director, Australian Research Centre for Human Evolution, Griffith UniversityMahmoud Abbas, Postdoctoral Research Fellow, Institute of Marine Sciences, Shantou UniversityZhongping Lai, Professor, Institute of Marine Sciences, Shantou UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1669402022-04-19T12:20:59Z2022-04-19T12:20:59ZHow a South African community’s request for its genetic data raises questions about ethical and equitable research<figure><img src="https://images.theconversation.com/files/447331/original/file-20220218-43570-jbyp9t.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2941%2C1959&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many researchers are interested in the genetic history of the Khoe-San.</span> <span class="attribution"><span class="source">Dana Al-Hindi</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Scientists believe Africa is where <a href="https://www.pbs.org/newshour/science/cradle-of-modern-human-life-found-in-botswana-maybe">modern humans first emerged</a>. For the past decade, our team of <a href="https://scholar.google.com/citations?user=sDUNh9UAAAAJ&hl=en">genetic</a> <a href="http://hennlab.ucdavis.edu/dana-al-hindi.html">researchers</a> from the <a href="http://hennlab.ucdavis.edu/">Henn Lab</a> have worked among the Khoe-San and self-identified “<a href="https://www.semanticscholar.org/paper/What%27s-in-a-name-Racial-categorisations-under-and-Posel/81e1ad38d1f37b37fe1cddd8a81081b378242217">Coloured</a>” communities in South Africa, which comprise multiple ethnic groups in the region, requesting DNA and generating genetic data to help unravel the history and prehistory of southern Africans and their relationship to populations around the world. </p>
<p>While we have learned a great deal from these communities, we have been unable to fulfill a common request: providing them their individual genetic ancestry results. In our attempts to overcome the logistical challenges of providing this information, we’ve grappled with the common question of how to ensure an equitable balance of benefits between researchers and the community they study. What we’ve found is that there is no easy answer. </p>
<h2>The history of the Khoe-San</h2>
<p>Community member requests to see their genetic results came as no surprise. Many South African groups were stripped of their identities and collapsed into one overarching racial category known as “<a href="https://doi.org/10.1016/S1090-9524(03)00007-X">Coloured</a>” during the early 1900s. Early <a href="https://muse.jhu.edu/book/35209">European colonizers</a> initially used this term to refer to indigenous Khoekhoe and San groups long before it was codified by the apartheid government in 1948. It persists today as an ethnic category, broadly encompassing Khoe-San groups, various East African, Indian and Southeast Asian populations brought by the slave trade, and people of mixed ancestry. </p>
<p><a href="https://doi.org/10.1534/genetics.116.187369">We</a> and <a href="https://doi.org/10.1126/science.1227721">other</a> research groups have shown that some Coloured communities are largely descendants of the Khoe and San peoples. Other ancestries present in Coloured communities are from Bantu-speaking populations that migrated into the region from <a href="https://doi.org/10.1093/hmg/ddaa274">western Africa</a> around 1,500 years ago and from <a href="https://doi.org/10.1186/s12915-020-0746-1">Europe</a> a little under 400 years ago. <a href="https://doi.org/10.1186/s12915-020-0746-1">Asian ancestry</a> is also present as a result of the aforementioned slave trade.</p>
<p>The Khoe and San are considered the most <a href="https://doi.org/10.1073/pnas.1017511108">genetically diverse</a> human populations currently known, meaning they have a large amount of genetic differences within and between each community. Though they are distinct groups, they share genetic similarities with each other. As a result, geneticists collectively refer to them as <a href="https://doi.org/10.1038/464487a">Khoe-San</a>, using a hyphen to acknowledge their cultural distinction.</p>
<p>Today, few people identify as Khoe or San in South Africa. Rather, many people call themselves Coloured, though they are deeply aware of the term’s racist legacy. </p>
<h2>Logistical challenges and potential risks</h2>
<p>In our 12 years of fieldwork, we have returned to South Africa on a nearly annual basis to update community-level genetic results. At each visit, most of our participants ask about their personal genetic ancestry results. </p>
<p>But there are several hurdles we face in trying to fulfill their requests. For one, we need to be able to translate scientifically complex data into an accessible and digestible form, a skill that researchers are not always equipped with. Additionally, we must work within restrictions set by <a href="http://www.sun.ac.za/english/faculty/healthsciences/rdsd/Documents/Ethics/DoH%202015%20Ethics%20in%20Health%20Research%20-%20Principles,%20Processes%20and%20Structures%202nd%20Ed.pdf">the local government</a>, which is mediated by the Health Research Ethics Committee at our collaborators’ academic institution, as well as restrictions set by the <a href="http://trust-project.eu/wp-content/uploads/2017/03/San-Code-of-RESEARCH-Ethics-Booklet-final.pdf">South African San Council</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Enrolled research participant holding the spitkit during saliva collection" src="https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=612&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=612&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=612&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=770&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=770&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449876/original/file-20220303-4451-15ykg4f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=770&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers extracted DNA from saliva samples.</span>
<span class="attribution"><span class="source">Dana Al-Hindi</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
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<p>There are also <a href="https://www.ncbi.nlm.nih.gov/books/NBK525077/">potential risks</a> to the participant. Group-level results provide a protective blanket from potential legal or social issues that can arise from individual ancestry results. For example, a participant may learn that their biological father is not who they believed they were, which could sow conflict in the family and unease for the participant. More generally, the participant faces the social risk of being included or excluded from different communities depending on the outcome of the results.</p>
<p>We discussed these potential problems with past participants and found that most community members care little about the risks. Our participants have consistently viewed the option to receive their personal ancestry results as a benefit of taking part in research. They simply want to know who their forefathers were.</p>
<h2>Helicopter research and exploitation</h2>
<p>To fulfill these requests, we’ve partnered with <a href="https://www.23andme.com/">23andMe Inc.</a>, a U.S.-based company that provides at-home genetic testing. One of us previously worked for 23andMe on its ancestry team and continues to maintain a relationship with scientists at the company. When 23andMe launched a <a href="https://blog.23andme.com/23andme-research/23andmes-populations-collaborations/">program in 2018</a> to improve genetic data on underrepresented communities in biomedical and genetic research, we were excited to see an emphasis on local partnerships and community grants. We submitted a successful application, and 23andMe has provided us with funding to conduct this research.</p>
<p>As academic researchers, we don’t always have the right expertise on how to best communicate personal results. Nor do we often have the funds to successfully execute this task. Research grants do not typically provide support for community development, and graduate and postdoctoral researchers lack protected time to do this on top of their other responsibilities. 23andMe, on the other hand, already has the resources and the experience to accessibly communicate personal genomic results to lay people, because that’s its commercial product. Thus, collaborations with for-profit organizations is not uncommon. Along with <a href="https://doi.org/10.1101/2022.02.07.478793">23andMe</a>, academic researchers have also worked with genetic testing companies <a href="https://www.forbes.com/sites/tommywilliams1/2020/02/29/meet-54gene-changing-the-landscape-of-global-dna-by-including-africa/?sh=6a92cbc55abd">54gene</a> and <a href="https://medium.com/variantbio/variant-bio-launches-new-partnership-on-kidney-disease-in-south-africa-ef3657fb4f3d">Variant Bio</a>.</p>
<p>With approval from the research ethics committee of the local university we work with, 23andMe will fund the expenses of our fieldwork and a community grant, in addition to processing our DNA samples in exchange for data access. They plan to use the data to improve African ancestry results for their customers and for their own research projects. </p>
<p>The company made <a href="https://www.bloomberg.com/news/features/2021-11-04/23andme-to-use-dna-tests-to-make-cancer-drugs">over US$50 million</a> in 2021, and its plans to use the genetic data it has accumulated from its customers to develop pharmaceuticals has not been without <a href="https://www.nytimes.com/2021/09/20/opinion/23andme-dna.html">controversy</a> in the U.S. The samples collected in our partnership with 23andMe, however, would not be used to develop new drugs. While our research focuses primarily on broadening scientific knowledge, and 23andMe does make an effort to follow an <a href="https://blog.23andme.com/23andme-research/an-ethical-framework-for-international-research/">ethical framework</a> for collaborations like these, our developing partnership has heightened our concerns about exploitation and what’s known as <a href="https://doi.org/10.1038/d41586-021-01795-1">helicopter research</a>.</p>
<p>Scientists conduct helicopter research when they collect data from developing countries and marginalized communities with little to no involvement from local researchers and community members. Helicopter research also occurs when researchers take data out of the country they collected it from without either providing benefit to or sharing the results with the community.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/HOBlWaH-Owo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Informed consent is not enough to prevent research from being exploitative.</span></figcaption>
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<p>San communities are <a href="https://www.smithsonianmag.com/smart-news/san-people-south-africa-issue-code-ethics-researchers-180962615/">no strangers</a> to helicopter research. For example, <a href="https://doi.org/10.1007/978-90-481-3123-5_6">hoodia</a> is a cactus San communities use to suppress appetite during long hunts or famine. Pharmaceutical companies researched and patented this cultural knowledge in 1995 to develop and sell an anti-obesity pill, initially all without San recognition or involvement. If the San were acknowledged at all, they were referred to as a <a href="https://uwapress.uw.edu/book/9780295742175/reinventing-hoodia/">population that no longer existed</a>. After several legal disputes, the San were promised benefits from any production that came out of the project. Though they received <a href="https://www.unl.edu/rhames/courses/current/hoodia.htm">some compensation</a>, it was a fraction of the value they funneled toward the research and <a href="https://uwapress.uw.edu/book/9780295742175/reinventing-hoodia/">nowhere near what was promised</a>.</p>
<p>This has been a recurring issue for the Khoe and San communities, most recently involving the <a href="https://doi.org/10.1038/d41586-019-03374-x">rooibos tea industry</a>. Companies conducted over a century of commercial rooibos farming benefiting from Khoe and San cultural knowledge before finally agreeing to pay 1.5% of what farmers make for unprocessed rooibos to the communities. Because of this, gaining approval from the local university’s ethics committee for our project has been difficult, and understandably so.</p>
<p>To build a more active and transparent relationship with the local community, we are working closely with 23andMe to develop an advisory board of members from local communities. We have held town halls and conducted interviews with locals to ask if they’d still be interested in being a part of this research project if a company became involved. The majority expressed little concern about 23andMe’s involvement and potentially profiting from their genetic information. But history has shown that for study participants around the globe, <a href="https://doi.org/10.1017/S0963180111000259">informed consent</a> has its limitations. It is still difficult to communicate and gauge whether participants, or the <a href="https://www.vox.com/recode/2019/12/13/20978024/genetic-testing-dna-consequences-23andme-ancestry">millions of Americans</a> who have paid 23andMe for genetic testing, fully understand the full extent of the risks involved with giving away their genetic data, both to 23andMe and to us academic researchers.</p>
<p>The company has offered to provide small community grants to help meet local needs, and has also expanded our ability to “<a href="https://www.un.org/en/academic-impact/capacity-building">capacity-build</a>” – that is, to make sure that the knowledge and skills we gain are shared with local institutions. But the question remains whether there is an equitable balance of benefits. Other companies have already promised <a href="https://54gene.com/we-have-launched-a-trust-to-reinvest-5-of-proceeds-from-commercial-drug-discovery-programs-on-african-scientists-and-communities/">long-term benefits</a> by <a href="https://www.variantbio.com/faq">sharing equity and profit</a> with participating communities. Are individual ancestry results and community grants a sufficient and fair exchange against the profits the company will gain from this collaboration?</p>
<h2>Where does this leave us?</h2>
<p>Academic researchers are faced with navigating the many trade-offs that come with industry collaborations. While 23andMe’s participation provides a means to return individual results to the community, it also raises questions about sufficiently equitable benefits. Our research team, local collaborators and 23andMe are all concerned about how to best address the risk of helicopter research, coercion and any unknown risks that may arise from disclosing personal ancestry results. </p>
<p>In an ideal world, researchers would be able to return benefits to the community without involving nonacademic external parties. Integrating practices like returning results to communities within <a href="https://doi.org/10.1371/journal.pcbi.1009277">research grant requirements</a> is one way to ensure that participants are also benefiting from research. Nonprofit small grants dedicated to returning results and community benefit are another. Until then, researchers will continue to make do with the limited resources they have.</p>
<p><em>This article was updated to more accurately reflect how 23andMe will use the collected data.</em></p><img src="https://counter.theconversation.com/content/166940/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dana Al-Hindi intends to use Dr. Henn's awarded funds from 23andMe Inc. to complete fieldwork and return of results to sampled communities. </span></em></p><p class="fine-print"><em><span>Brenna Henn is a former employee of 23andMe, Inc. and retains shares in the organization. She has received funding from 23andMe to complete research described in this article. </span></em></p>The South African Khoe-San communities are no strangers to exploitative research. One research team is trying to provide genetic ancestry results to community members. But they still face many challenges.Dana Al-Hindi, PhD Candidate in Anthropology, University of California, DavisBrenna Henn, Associate Professor of Anthropology, University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1670502021-09-01T20:10:52Z2021-09-01T20:10:52ZResearch reveals humans ventured out of Africa repeatedly as early as 400,000 years ago, to visit the rolling grasslands of Arabia<figure><img src="https://images.theconversation.com/files/418801/original/file-20210901-13-u6hxli.jpg?ixlib=rb-1.1.0&rect=22%2C16%2C1352%2C740&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Eleanor Scerri</span>, <span class="license">Author provided</span></span></figcaption></figure><p>If you stood in the middle of the Nefud Desert in central Arabia today, you’d be confronted on all sides by enormous sand dunes, some rising more than 100 meters from the desert floor. </p>
<p>The few scraggly bushes make poor browse for the herds of goats and camels that eke out a living in this harsh environment. But this wasn’t always the case.</p>
<p>Our research published today in <a href="https://www.nature.com/articles/s41586-021-03863-y">Nature</a> shows that in repeated pulses over the past 400,000 years, the Nefud Desert landscape received monsoon rains that resulted in rolling grasslands, flowing rivers and large lakes home to thousands of wild donkeys, antelopes and hippos.</p>
<p>Humans also inhabited these green corridors as they made their way out of Africa, only to disappear when conditions deteriorated again. </p>
<p>Among other findings, we present the oldest dated evidence for hominins in Arabia, in the form of stone tools dated to about 400,000 years ago. The Homininae subfamily is the group of humans of which <em>Homo sapiens</em> is the sole survivor. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=292&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=292&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=292&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=367&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=367&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418793/original/file-20210901-15-1rcoh1e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=367&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 400,000 year ‘handaxe’ stone tool from Khall Amayshan 4.</span>
<span class="attribution"><span class="source">Palaeodeserts Project (photo by Ian Cartwright)</span></span>
</figcaption>
</figure>
<h2>Early movements out of Africa</h2>
<p>Today Arabia is one of the world’s driest places, and was long thought to have played little role in human prehistory. </p>
<p>While the rich and long-studied Levant and the Mediterranean regions were considered critical for the dispersal of people out of Africa, it was thought most humans would have avoided places like the Arabian “Empty Quarter” — due to the harshness of its environmental conditions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418773/original/file-20210831-19-1s6hphj.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"></a>
<figcaption>
<span class="caption">The Nefud Desert today.</span>
<span class="attribution"><span class="source">Julien Louys</span></span>
</figcaption>
</figure>
<p>But detailed scientific investigations over the past few decades have been slowly changing these ideas. A rich stone tool culture has now been recovered from the surfaces of many ancient and dried out lakebeds in Southwest Asia. </p>
<p>However, because these were from isolated beds — often hundreds of kilometres apart — and restricted to surface scatters, it was difficult to determine who had left these tools, when, and where they came from.</p>
<p>In collaboration with the Heritage Commission of the Saudi Ministry of Culture and other Saudi colleagues, our international team of researchers has been working in Saudi Arabia, Southwest Asia’s largest country, for the past decade. </p>
<p>We have recorded and studied a wealth of stone tools and animal fossils emerging from the sands and ancient lakebeds. And we’ve made some startling discoveries. </p>
<p>We recovered a <em>Homo sapiens</em> finger bone, among other fossils, from an ancient Saudi Arabian lakebed known as <a href="https://www.nature.com/articles/s41559-018-0518-2">Al Wusta</a>. These remains were dated to 85,000 years ago. This finding shows modern humans had made it out <a href="https://theconversation.com/our-fossil-finger-discovery-points-to-earlier-human-migration-in-arabia-94670">of Africa at least 20,000 years before</a> the genetic evidence indicates we left. </p>
<p>It has been thought (and many still believe) <em>Homo sapiens</em> only left Africa about 50-65,000 years ago. Our finger bone finding challenges this view, as do other discoveries - including from Madjedbebe in Australia. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">Buried tools and pigments tell a new history of humans in Australia for 65,000 years</a>
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</p>
<hr>
<p>What happened to the group of people from Al Wusta remains unknown. They may have moved further into Asia, or retreated back to Africa. Or they may have become locally extinct.</p>
<h2>A green Arabia</h2>
<p>We also report a series of archaeological sites associated with multiple lakes across two locations which tell the story of human prehistory going back 400,000 years. The first of these locations, Khall Amayshan 4, is a depression located between large sand dunes covering 60,000 square metres. </p>
<p>In this single depression we found individual lakebeds dated back to 55,000, 100,000, 200,000, 300,000 and 400,000 thousand years ago. And each of the five lake phases is represented by its own unique archaeological signature.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418774/original/file-20210831-29-9oaf0z.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"></a>
<figcaption>
<span class="caption">Aerial view of Khall Amayshan 4 showing the series of ancient lakebeds. See the two small, white 4WDs on the left for scale.</span>
<span class="attribution"><span class="source">Julien Louys</span></span>
</figcaption>
</figure>
<p>Today different populations around the world can be identified by their cultures, which include the tools they use, how they’re made and how they use them. Think chopsticks across Asia and forks in Europe, for example. </p>
<p>These tools are passed on to successive generations, even if those generations move from their point of origin. The way people made and used stone tools in the past also reflected patterns of cultural inheritance. </p>
<p>So by studying and comparing the stone tools from Arabia with those from surrounding regions, we can find out not just when people were living and moving through the region, but also where their ancestors had moved from and how they changed as they moved.</p>
<p>The most striking thing we found was that each assemblage of stone tools recovered from each ancient lakebed was very different from the others. </p>
<p>Our detailed examination of the lakebeds and the mammal fossils they preserved, including from hippos, clearly pointed to how much wetter, greener and more productive each of those phases were compared to the region today. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418796/original/file-20210901-13-2w4jz1.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"></a>
<figcaption>
<span class="caption">Antelope teeth eroding from an ancient lakebed in the Nefud Desert.</span>
<span class="attribution"><span class="source">Julien Louys</span></span>
</figcaption>
</figure>
<p>The different technologies associated with each green phase indicate there was no long-term continuity in the populations in the area. Instead, different populations, perhaps even different species of hominin, were moving in and out with each phase. </p>
<p>At the Jubbah Oasis around 150 km east of Khall Amayshan 4, two further sites – Jebel Qattar 1 and Jebel Umm Sanman 1 – filled in the last of the gaps in the timeline. These sites presented different stone tools dating to around 200,000 and 75,000 years ago, also associated with green phases. </p>
<p>Each of these phases occurs during wetter climatic periods, which are wetter due to the northern movements of the monsoon, bringing increased rainfall to the desert. Once the climate shifted back, however, conditions became arid again and humans and other fauna disappeared from Arabia. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/prehistoric-desert-footprints-are-earliest-evidence-for-homo-sapiens-on-arabian-peninsula-146445">Prehistoric desert footprints are earliest evidence for Homo sapiens on Arabian Peninsula</a>
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<p>Our findings reveal the intimate association between early human migrations and patterns of climate change — wherein different groups of humans repeatedly made it out of Africa when conditions became favourable. </p>
<p>And this happened long before the dispersal event of 50-65,000 years ago, which finally saw their descendents permanently colonise other regions.</p>
<p>Yet dozens of questions remain. Were some of these migrations from northern Neanderthals? What became of these different populations? Where did they go? Could some have made it to Southeast Asia and hence to Australia? </p>
<p>The human story won’t be told completely until we explore more long-neglected areas, much like our ancestors once did.</p><img src="https://counter.theconversation.com/content/167050/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julien Louys receives funding from The Australian Research Council and the Leakey Foundation</span></em></p><p class="fine-print"><em><span>Gilbert Price receives funding from The Australian Research Council and the Leakey Foundation.</span></em></p><p class="fine-print"><em><span>Huw Groucutt receives funding from the Max Planck Society.</span></em></p><p class="fine-print"><em><span>Michael Petraglia receives funding from the European Research Council and the Max Planck Society. </span></em></p>The new work presents the oldest dated evidence for hominins in Arabia, in the form of an ancient handaxe tool uncovered from the Nefud Desert.Julien Louys, Deputy Director, Australian Research Centre for Human Evolution, Griffith UniversityGilbert Price, Lecturer in Palaeontology, The University of QueenslandHuw Groucutt, Group leader of Max Planck 'Extreme Events' group., Max Planck Institute of GeoanthropologyMichael Petraglia, Professor of Archaeology, Max Planck Institute of GeoanthropologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1258142019-10-28T19:06:33Z2019-10-28T19:06:33ZHumanity’s birthplace: why everyone alive today can call northern Botswana home<figure><img src="https://images.theconversation.com/files/298877/original/file-20191028-113980-qj9kj9.jpeg?ixlib=rb-1.1.0&rect=4%2C25%2C894%2C573&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researcher Vanessa Hayes with the Ju/’hoansi people in the ancestral homeland of humanity.</span> <span class="attribution"><span class="source">Chris Bennett/Evolving Picture</span></span></figcaption></figure><p>Where was the evolutionary birthplace of modern humans? The East African Great Rift Valley has long been the favoured contender – until today. </p>
<p>Our new research has used DNA to trace humanity’s earliest footsteps to a prehistoric wetland called Makgadikgadi-Okavango, south of the Great Zambezi River.</p>
<p>Our analysis, <a href="https://doi.org/10.1038/s41586-019-1714-1">published in Nature today</a>, shows that the earliest population of modern humans (<em>Homo sapiens sapiens</em>) arose 200,000 years ago in an area that covers parts of modern-day Botswana, Namibia and Zimbabwe. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=335&fit=crop&dpr=1 600w, https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=335&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=335&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=421&fit=crop&dpr=1 754w, https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=421&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/298878/original/file-20191028-113953-1lj35xj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=421&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 left map shows the distribution of ancestral DNA among the sampled population. This allowed the ancestral homeland to be pinpointed to a region (shown on the right in pale orange) south of the Zambezi River, centred on northern Botswana.</span>
<span class="attribution"><span class="source">Chan et al., Nature 2019</span></span>
</figcaption>
</figure>
<p>Today it is a dry and dusty land with scattered salt pans, and it is hard to believe that modern humans lived and thrived in wetlands here for 70,000 years before our ancestors began to explore the rest of Africa, and ultimately the world.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ancestors-a-new-game-provides-insights-into-how-the-first-humans-evolved-123318">'Ancestors': a new game provides insights into how the first humans evolved</a>
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<p>We pinpointed this region by studying mitochondrial DNA, known as the “mitogenome”. Unlike nuclear DNA, which is passed on by both mother and father, mitochondrial DNA is passed on only by the mother, which means it is not jumbled up in each generation.</p>
<p>If we think of all modern humans as occupying a particular place on a huge family tree, logically we should find the most diverse mitogenomes at the very base of the tree, because it is the ultimate source of all the various branches.</p>
<p>We already know that genetic data points to southern Africa as the cradle of humanity (unlike fossil evidence, most of which has been found in East Africa). But we wanted to refine our search still further, to pinpoint the exact location where humans first evolved.</p>
<p>To do this, we turned our attention to a group of people known as the KhoeSan. KhoeSan have the most diverse mitogenomes of anyone on Earth, which suggests their DNA most closely resembles that of our shared common ancestors. If we all sit on branches of the human family tree, then KhoeSan are the tree’s trunk.</p>
<p>Linguistically, KhoeSan people are click speakers, while culturally KhoeSan are foragers, with groups of San people still practising the old ways of life – hunting and gathering for subsistence.</p>
<p>Members of our research team have spent a decade working with KhoeSan communities, as well as people from other ethnicities and language groups, in Namibia and South Africa.</p>
<p>By generating mitogenome data for around 200 rare or newly discoverd sub-branches of KhoeSan lineages, and merging them with all available data, we were able to zoom in on the very base of our evolutionary tree.</p>
<p>It is now clear our ancestors must have dispersed from a region south of the Zambezi River. This is consistent with geographical, archaeological and climate data, including the fact that this area would have been a fertile wetland at the time the first modern humans emerged.</p>
<h2>Lush landscapes</h2>
<p>Geological evidence suggests that at this time, the prehistoric Makgadikgadi lake that had dominated the region for millions of years had begun to break up through the shifting of the land. This would have created a vast wetland region, ideal to sustain life. </p>
<p>But if it was so ideal, why did our ancestors begin to explore other places between 130,000 and 110,000 years ago, first heading northeast and later southwest from the ancestral home? </p>
<p>Climate data suggests that at around that time the region experienced a huge drought. Notably, about 130,000 years ago humidity increased to the northeast of the homeland, and 110,000 years ago the same happened to the southwest. We speculate that this created passages of lush vegetation for our ancestors to leave the homeland, most likely following the game animals that were also forging into new regions.</p>
<p>What’s more, our genetic data suggests the southerly migrants went on to inhabit the entire southern coast of Africa, with multiple sub-populations and huge population growth. Archaeological findings from the Blombos caves in South Africa have shown this region to be rich in evidence for cognitive human behaviour as early as 100,000 years ago. Again, we were amazed at how well we could match timeline data, crossing different yet complimentary disciplines that have historically not worked together. This also allowed us to further speculate about the success of the southerly migrants being attributed to adapting their skills to the abundance of life in the oceans.</p>
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Read more:
<a href="https://theconversation.com/ancient-dna-is-a-powerful-tool-for-studying-the-past-when-archaeologists-and-geneticists-work-together-111127">Ancient DNA is a powerful tool for studying the past – when archaeologists and geneticists work together</a>
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<p>These earliest explorers left behind a homeland population, one that still remains within the ancestral lands today, having adapted to the much drier landscape. It has been a pleasure to spend the past decade engaging with the last descendants of humanity’s homeland, including the Ju/’hoansi people of the Kalahari in Namibia. </p>
<p>The Ju/’hoansi, who still practise their traditional way of life, are excited about our findings. They believe our study captures a history that they have told for generations by word of mouth alone. This is not only their story, but all of ours.</p><img src="https://counter.theconversation.com/content/125814/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa Hayes receives funding from Australian Research Council Discovery Project grant (DP170103071) and holds the Sydney University Petre Chair of Prostate Cancer Research. She is affiliated with the University of New South Wales Sydney, as well as the University of Pretoria and University of Limpopo in South Africa. </span></em></p>Genetic analysis has traced the evolutionary footsteps of modern humans all the way back to a prehistoric wetland that spanned parts of modern-day Botswana, Namibia and Zimbabwe.Vanessa Hayes, Professor, Garvan Institute of Medical Research and, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1007522018-08-02T23:18:12Z2018-08-02T23:18:12ZWe know why short-statured people of Flores became small – but for the extinct ‘Hobbit’ it’s not so clear<figure><img src="https://images.theconversation.com/files/230340/original/file-20180802-136652-1p40tmn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rampasasa people are from Waemulu village, Flores – near Liang Bua where 'the Hobbit' fossils were discovered. </span> <span class="attribution"><span class="source">Dean Falk, Florida State University </span>, <span class="license">Author provided</span></span></figcaption></figure><p>Humans are diverse in size and shape – but some populations are of relatively low average height, and historically described using the term “pygmy”. Some researchers have suggested that the Rampasasa inhabitants of the Flores highlands of Indonesia are one such group.</p>
<p>A paper published today in <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aar8486">Science</a> looked at whether the Rampasasa are related to an ancient human-like being that was also small in stature and once lived on the island of Flores – the archaic hominin <em>Homo floresiensis</em>, commonly referred to as “<a href="https://www.nature.com/news/the-discovery-of-homo-floresiensis-tales-of-the-hobbit-1.16197">the Hobbit</a>”. The Rampasasa live near Liang Bua, where the Hobbit fossils were first discovered. </p>
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<a href="https://theconversation.com/the-hobbit-took-our-breath-away-now-its-the-new-normal-60784">The Hobbit took our breath away: now it's the new normal</a>
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<p>The study finds no evidence of a genetic relationship – which isn’t surprising, even though a <a href="http://www.pnas.org/content/103/36/13421.short">paper published in 2006</a> suggested otherwise.</p>
<p>The key claim made by today’s paper is that there have been two independent cases of insular dwarfism (reduction in size over time) evolving on Flores: one in our species <em>Home sapiens</em>, and another that resulted in the emergence of <em>Homo floresiensis</em>. </p>
<p>But is this really the case? </p>
<h2>Short-statured humans</h2>
<p>In anthropology, the term “pygmy” refers to populations with an average male stature of less than 150cm and an average female stature of less than 140cm – here we’ll use the term “short-statured”. </p>
<p>There are true short-statured populations to this day in the Andaman Islands (north of Sumatra) and the African rainforests, and borderline peoples in the rainforests of the Malay Peninsula and the Philippines. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230330/original/file-20180802-118933-1szsx7x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&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">Short-statured Baka men preparing to hunt with nets in the Dzanga-Sangha Forest Reserve, Central African Republic.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dzangasangha-forest-reserve-centralafrican-republic-car-451013683?src=3dp-gdzWMDkPbGRc_1MWWw-1-6">Sergey Uryadnikov / Shutterstock.com</a></span>
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<p>Across Africa, South Asia and South East Asia, short-statured populations in the past were interpreted as representing a single ancient migration out of Africa of modern humans who all shared a close ancestry.</p>
<p>Even in Australia, it was considered by one anthropologist (<a href="https://en.wikipedia.org/wiki/Joseph_Birdsell">Dr Joseph Birdsell</a>) that short-statured Indigenous people living in the closed rainforests behind Cairns were part of this first ancient migration of modern humans. </p>
<p>This hypothesis came <a href="https://www.jstor.org/stable/24046693?seq=1#page_scan_tab_contents">undone</a> through a better understanding of the <a href="https://www.nature.com/articles/nature18299">genetic diversity</a> of these populations and improved knowledge of how modern humans <a href="https://www.sciencedirect.com/science/article/pii/S0169534709000421">adapt</a> to closed forests – including in <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.20640">Australia</a>. </p>
<h2>The stature of the Rampasasa</h2>
<p>According to <a href="http://www.worldcat.org/title/anthropological-survey-of-the-eastern-little-sunda-islands-the-negritos-of-the-eastern-little-sunda-islands-the-proto-malay-of-the-netherlands-east-indies/oclc/609580">1940s data</a> collected by enigmatic anthropologist W. Keers, average male stature varied between 154cm and 163cm in the Indonesia’s Flores highlands, central Timor and Sumba. They are short people, yes, but not so-called “pygmies” by classical definition. </p>
<p>The same would apply to the Rampasasa, based on their <a href="http://www.pnas.org/content/103/36/13421.short">average stature of 146cm</a> across 35 males and 41 females. Given this is a mixed sex sample, it’s somewhat confusing that the new <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aar8486">Science paper</a> refers to the Rampasasa as “pygmies”. </p>
<p>Semantics aside, the tiny stature of 110cm for “the Hobbit” <em>Homo floresiensis</em> (female) type is well below the recorded range for modern humans, “pygmy” or otherwise. Various attempts have been made to attribute the tiny stature of “the Hobbit” to diseases such as <a href="http://www.pnas.org/content/103/36/13421.short">microcephaly</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0018442X12001102">cretinism</a>, <a href="http://www.pnas.org/content/111/33/11967">Down sydrome</a> and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.20655">Laron syndrome</a>. </p>
<p>However these attempts have been unsuccessful in explaining the unique suite of <em>Homo floresiensis</em> characteristics that clearly distinguish it from <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155731">any modern humans</a>.</p>
<h2>The ‘Hobbit’ was tiny</h2>
<p>The existence of “the Hobbit” is based on an original fossil reported at <a href="https://www.nature.com/news/the-discovery-of-homo-floresiensis-tales-of-the-hobbit-1.16197">Liang Bua in 2004</a>, and possibly additional evidence located at the earlier site of Mate Menge <a href="https://www.nature.com/articles/nature17999">reported in 2016</a> </p>
<p>So how could <em>Homo floresiensis</em> have developed its unique features, of which tiny size is just one? </p>
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<a href="https://theconversation.com/down-syndrome-theory-on-hobbit-species-doesnt-hold-to-scrutiny-33375">Down syndrome theory on Hobbit species doesn't hold to scrutiny</a>
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<p>According to archaeological evidence, their ancestors arrived on Flores approximately a million years ago, which allows ample time for evolution through isolation of a species (if we accept the Mate Menge fossil as also being <em>Homo floresiensis</em>) dated to 700,000–60,000 years ago. </p>
<p>Some palaeoanthropologists argue that the Hobbit direct ancestor was the Asian hominin <em><a href="https://australianmuseum.net.au/homo-erectus">Homo erectus</a></em>, commonly referred to as “Java Man” because it inhabited Java from about 1.7 million years ago until sometime before 100,000 years ago. </p>
<p><a href="https://en.wikipedia.org/wiki/Foster%27s_rule">Insular dwarfing</a> may explain the tiny size (and remarkably small braincase) of the Hobbit, but it does not easily explain the other features of the skull and lower skeleton that appear more primitive than recorded for <em>Homo erectus</em>. </p>
<p>A number of scientists employing <a href="https://evolution.berkeley.edu/evolibrary/article/phylogenetics_01">phylogenetic techniques</a> that are commonly used across palaeontology propose that a more ancient hominin, perhaps one more closely related to <em><a href="http://humanorigins.si.edu/evidence/human-fossils/species/homo-habilis">Homo habilis</a></em> must have reached Flores to give rise to the Hobbit. </p>
<p>Recent <a href="https://theconversation.com/humankinds-odyssey-from-africa-began-more-than-two-million-years-ago-99671">archaeological finds in China</a> dated to 2.1 million years ago support the idea that an older, pre-erectus hominin may have been present in Asia. </p>
<p>More fossil evidence is required before we can confidently classify the Hobbit, and establish if it is derived from <em>Homo erectus</em> or whether it represents a so-called “pre-erectus” hominin.</p>
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Read more:
<a href="https://theconversation.com/humankinds-odyssey-from-africa-began-more-than-two-million-years-ago-99671">Humankind's odyssey from Africa began more than two million years ago</a>
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<h2>Modern humans in Southeast Asia</h2>
<p>Modern humans first moved into the region of Island Southeast Asia as early as <a href="https://www.nature.com/articles/nature22968">65,000</a> years ago, heralding the seaborne colonisation of Australia and New Guinea. A later migration of modern humans from Northeast Asia occurred into Island Southeast Asia in the last <a href="http://press-files.anu.edu.au/downloads/press/p69411/mobile/ch05s02.html">4,000</a> years. </p>
<p>Different physical characteristics in peoples in this region may reflect these two migrations. </p>
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Read more:
<a href="https://theconversation.com/worlds-scientists-turn-to-asia-and-australia-to-rewrite-human-history-88697">World's scientists turn to Asia and Australia to rewrite human history</a>
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<p>The Science paper did find a small genetic contribution to the Rampasasa from two other archaic populations, but this does not distinguish them from other modern humans in the region. </p>
<p>One of these archaic populations is the Neanderthals, whose genetic signature is present in <a href="https://genographic.nationalgeographic.com/neanderthal/">all modern humans outside of Africa</a>. The other is the Denisovans, <a href="https://genographic.nationalgeographic.com/denisovan/">whose DNA</a> is known only from a finger bone found in a Siberian cave. </p>
<p>Denisovans have been identified as a minor contributor to the DNA of populations today in the Philippines, the islands near Flores, with slightly <a href="https://www.sciencedirect.com/science/article/pii/S0002929711003958">higher frequencies</a> in the DNA of people from New Guinea and Australia.</p>
<p>The genetic data obtained for the Rampasasa are entirely compatible with a dual ancestry as also found for other eastern Indonesians. </p>
<h2>A unique finding related to diet</h2>
<p>Perhaps the major contribution made by the <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aar8486">Science paper</a> is its analysis of a group of genes known as the fatty acid desaturatase (FADS) gene cluster, and how this could modulate dietary related selection pressures. </p>
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Read more:
<a href="https://theconversation.com/the-origin-of-us-what-we-know-so-far-about-where-we-humans-come-from-54385">The origin of 'us': what we know so far about where we humans come from</a>
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<p>Where the diet is poor, the FADS gene cluster is shown to select for small stature. This mechanism could be of value in explaining the small stature of some populations (particularly in rainforests and on small islands), as well as other small-bodied individuals in some environments. </p>
<p>Indeed there may also be an insight here for understanding stature variation in archaic hominins like the Hobbit, if we are able to identify their genomes in ancient fossils or modern human sequences.</p><img src="https://counter.theconversation.com/content/100752/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Westaway receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>In 2006 Francis David Bulbeck received funding from the Australian Research Council to investigate whether microcephalic eastern Indonesian skulls could resemble Homo floresiensis.</span></em></p>Modern day people of short stature became physically small due to the effects of living on a small island or forested environment. But we’re not sure why “the Hobbit” of Flores was so small.Michael Westaway, Senior Research Fellow, Australian Research Centre for Human Evolution, Griffith UniversityFrancis David Bulbeck, Senior Research Associate, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/997602018-07-12T05:43:08Z2018-07-12T05:43:08ZRethinking Homo sapiens? The story of our origins gets dizzyingly complicated<figure><img src="https://images.theconversation.com/files/227144/original/file-20180711-27030-1931bkj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Homo sapiens_ evolved in the East African rift valley...but then what happened? </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/26781577@N07/27518854264/">26781577@N07/flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>You might say it’s the ultimate prize of science, to discover when, where and why humans evolved. </p>
<p>For a long time, the evidence has been overwhelming that <em>Homo sapiens</em> evolved in Africa and later spilled out of the continent to settle the rest of the planet. </p>
<p>But is the story of our origins really as simple as it seems? Published today, a <a href="https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(18)30117-4">new commentary</a> written by UK and German scientists suggests not. </p>
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Read more:
<a href="https://theconversation.com/curious-kids-where-did-the-first-person-come-from-85891">Curious Kids: Where did the first person come from?</a>
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<h2>Too easy, but then…</h2>
<p>A few years ago, it seemed all too easy. The matter was settled. <em>Homo sapiens</em> had evolved in the East African rift valley roughly 200,000 years ago and exited the mother continent to settle the remaining planet around 60,000 years ago.</p>
<p>But after decades of thinking we’d made major inroads into solving this ultimate riddle, the story of our origins is starting to get a long overdue overhaul.</p>
<p>A string of recent discoveries has pushed <a href="https://www.npr.org/sections/health-shots/2017/06/07/531804528/315-000-year-old-fossils-from-morocco-could-be-earliest-recorded-homo-sapiens">our origins in Africa</a> back to more than 315,000 years ago – and suggested <em>sapiens</em> first <a href="https://theconversation.com/fossil-jawbone-from-israel-is-the-oldest-modern-human-found-outside-africa-90495">exited Africa</a> close to 194,000 years ago making it to <a href="https://www.sciencemag.org/news/2015/10/trove-teeth-cave-represents-oldest-modern-humans-china">southern China</a> soon after, perhaps by 139,000 years ago. </p>
<p>And to add further complexity, this initial “Out-of-Africa” seems to have been followed by one or more later movements, by different <em>sapiens</em> populations, that settled far flung places <a href="http://www.abc.net.au/news/science/2017-07-20/indigenous-discovery-how-do-we-know-how-old-it-is/8719334">such as Australia</a> by around 65,000 years ago. </p>
<p>We’ve also begun to find humans whose physical traits don’t fit with our preconceived notions of what <em>sapiens</em> should look like, such as the <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0024024">Iwo Eleru</a>, <a href="https://www.sciencedirect.com/science/article/pii/S004724840800242X?via%3Dihub">Nazlet Khater</a> and <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0143332">Red Deer Cave</a> people surviving quite late in various parts of Africa and in Asia. </p>
<p>Could they be hybrids we’ve wondered? Because after decades of scientists <a href="http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0020421">locking horns</a> over the issue, geneticists have finally proven that our ancestors mated with the <a href="https://www.nature.com/articles/nature12961">Neanderthals</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0960982216302470">Denisovans</a> and other archaic humans even <a href="http://www.pnas.org/content/early/2011/08/29/1109300108.short">in Africa</a>.</p>
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Read more:
<a href="https://theconversation.com/neanderthals-didnt-give-us-red-hair-but-they-certainly-changed-the-way-we-sleep-85173">Neanderthals didn't give us red hair but they certainly changed the way we sleep</a>
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<h2>Change in the wind</h2>
<p>Sure, it’s normal for science to be regularly brought up to date, with new discoveries shifting what we think we know and sometimes even extending knowledge into new places. </p>
<p>But as someone who’s kept a keen eye on developments in, and indeed actively researching, our evolution, it’s clear to me that there’s something’s going on here. Change is in the wind!</p>
<p>So profound is the shift underway in human origins science that it’s seen the unusual step of a team of 23 researchers (led by Eleanor Scerri of the University of Oxford) <a href="https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(18)30117-4">publish today’s new synthesis of the evidence</a> – and in doing so embrace the emerging picture of complexity and ditch the old simplistic ideas. Among their ranks are archaeologists, anthropologists, geneticists and climate specialists. </p>
<p>It reads like a manifesto, and outlines the major new research directions archaeology should follow to solve our puzzling origins. A key message is that none of these disciplines on their own is capable of doing it and going it alone. That approach only leads to us grasping for simple answers to complex questions.</p>
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Read more:
<a href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">Buried tools and pigments tell a new history of humans in Australia for 65,000 years</a>
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<h2>Big issues on the line</h2>
<p>There are number of big issues being wrestled with here. Among the major ones is acknowledgement of the fact that the physical variation that characterises our species around the planet today seems to have emerged only within the period 100,000-40,000 years ago. This has made identifying our ancestors and tracing their evolutionary history exceedingly difficult. </p>
<p>The cranium from <a href="http://www.bradshawfoundation.com/herto_skulls.php">Herto</a> in Ethiopia is a great example of a very ancient person who was undoubtedly a member of our species, but who doesn’t really fit neatly into the variation characterising any living group.</p>
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Read more:
<a href="https://theconversation.com/new-moroccan-fossils-suggest-humans-lived-and-evolved-across-africa-100-000-years-earlier-than-we-thought-78826">New Moroccan fossils suggest humans lived and evolved across Africa 100,000 years earlier than we thought</a>
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<p>How would this occur? It seems that for the first couple of hundred thousand years of our history, our African forebears lived in very small and geographically isolated populations which evolved more or less independently of each other.</p>
<p>At some point one or more of them gave rise to one or more populations of living people, some of whom exited Africa, and with no clear evidence for how this all came about.</p>
<p>This leads us onto another, and perhaps the most important issue of all. How do we define <em>Homo sapiens</em> in the first place? How will this process provide useful criteria for recognising our kind in the African fossil record 200,000, 300,000 or even 400,000 years ago? </p>
<h2>Defining <em>Homo sapiens</em></h2>
<p>The Smithsonian Institution has <a href="http://humanorigins.si.edu/evidence/human-fossils/species/homo-sapiens">provided a summary</a> of the major features we use to define our species but sadly many can’t easily be found on the skulls of our early African ancestors. </p>
<p>Does this mean they aren’t our forebears? Not necessarily, just that our current approach is pretty limited and we need to keep in mind that our earliest ancestors would have looked, well, ancestral! </p>
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Read more:
<a href="https://theconversation.com/worlds-scientists-turn-to-asia-and-australia-to-rewrite-human-history-88697">World's scientists turn to Asia and Australia to rewrite human history</a>
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<p>Finally, the complicated links between Ice Age climate change and environmental shifts in Africa acting as key drivers through natural selection and <a href="https://evolution.berkeley.edu/evolibrary/article/evo_24">genetic drift</a> are becoming better understood. These forces have shaped how we look and behave and continue to exert their influence over our biology <a href="https://www.sciencemag.org/news/2012/04/natural-selection-still-us">today</a>.</p>
<p>Despite all the progress we’ve made over the last decade in teasing apart our origins, the manifesto of Scerri and her team has more than a hint of “back to the future” about it. </p>
<p>As bold and ambitious as it is, it leaves me with far more questions than answers, and a lingering feeling that the issues are far more complicated than we’ve been prepared to admit until now.</p><img src="https://counter.theconversation.com/content/99760/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Darren Curnoe receives funding from the Australian Research Council. </span></em></p>A manifesto from 23 researchers challenges old models, and outlines the major new directions archaeology should follow to solve the puzzling origins of modern humans.Darren Curnoe, Associate Professor and Chief Investigator, ARC Centre of Excellence for Australian Biodiversity and Heritage, University of New South Wales, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/996712018-07-11T20:11:28Z2018-07-11T20:11:28ZHumankind’s odyssey from Africa began more than two million years ago<figure><img src="https://images.theconversation.com/files/227066/original/file-20180711-27030-1v51nmh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Looking for food, water and maybe adventure? </span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/N64wTMsjnXU">Unsplash </a></span></figcaption></figure><p>Can you imagine walking 14,000km? Trekking across wide savannas, down creek beds, along mountain chains in terrain that is new and home to foreign types of plants and animals? Can I eat this? What is that? </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/226920/original/file-20180710-70042-1y5fba6.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>
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<span class="caption">One of the 2 million-year-old stone tools discovered at Shangchen, China.</span>
<span class="attribution"><span class="source">Photograph courtesy of R. Dennell.</span></span>
</figcaption>
</figure>
<p>This long excursion – once thought only to have been attempted late in the journey of humankind – has been getting pushed further and further back in time thanks to advancing archaeological research. </p>
<p><a href="https://www.nature.com/articles/s41586-018-0299-4">Findings published in Nature</a> today have extended the start of our worldwide trekking back to beyond 2.1 million years ago. </p>
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Read more:
<a href="https://theconversation.com/worlds-scientists-turn-to-asia-and-australia-to-rewrite-human-history-88697">World's scientists turn to Asia and Australia to rewrite human history</a>
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<p>Previously, we knew that people were wandering around eastern Europe by 1.85 million years ago, as their bones and tools were discovered at a cave site called <a href="http://www.dmanisi.ge/page?id=2&lang=en">Dmanisi</a> in Georgia. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227069/original/file-20180711-27015-p539r2.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&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">Ancient sites of global hominin presence.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41586-018-0299-4">John Kappelman/Nature (no reuse)</a></span>
</figcaption>
</figure>
<p>Presented in the <a href="https://www.nature.com/articles/s41586-018-0299-4">new paper</a> today, evidence for this earlier – and further – human movement comes in the form of flaked stone tools found in sediments at Shangchen, in the southern Chinese Loess Plateau. </p>
<p>Some 96 tools were found <em>in situ</em> – that is, still in the ground and undisturbed – and have shapes and traces of working recognisable to the archaeologist as distinctly human-made. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/SrvPOkMs4U4?wmode=transparent&start=83" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How are stone tools made? An expert explains.</span></figcaption>
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<h2>Out of Africa? Or Asia?</h2>
<p>Who were these early explorers? All signs point to hominids of the genus <em>Homo</em> (simply meaning “man”) – early people, <a href="http://humanorigins.si.edu/evidence/human-family-tree">some of whom led to our modern selves</a>. </p>
<p>An onslaught of recent findings from Asia has prompted some researchers to suggest that humans came “<a href="https://www.newscientist.com/article/mg23931850-200-asias-mysterious-role-in-the-early-origins-of-humanity/">Out of Asia</a>”. However, while it appears that people were in this region very early, humanity remains an African invention. </p>
<p>Our earliest ancestors arose in Africa some 6 million years ago, although the earliest remains of those belonging to our branch of the family tree – that of <em>Homo</em> – only date back to 2.8 million years ago. A single jawbone found in Ethiopia pushed back the <a href="https://www.smithsonianmag.com/science-nature/oldest-human-fossil-unearthed-ethiopia-180954470/">origins of our genus some 400,000 years</a>. </p>
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Read more:
<a href="https://theconversation.com/age-of-jawbones-mean-the-origins-of-humans-just-got-older-38722">Age of jawbones mean the origins of humans just got older</a>
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<p>Currently, it seems that the earliest communities of <em>Homo</em> lived in eastern Africa for several hundred thousand years before heading out and away from the motherland. </p>
<h2>Human = adaptable = global conquest</h2>
<p>The apparent ease with which humankind has moved across vast landscapes continues to surprise scientists. Many of us now struggle with a hike that our ancestors would consider a relaxing stroll down the road. So how far did they walk at any one time? </p>
<p>Realistically, we have no way of answering this question for sure. Modern hunter-gatherers such as the Hadza regularly travel some ten (or more) kilometres each day in the course of their daily activities. Applying this rate of movement, someone could theoretically reach the new Chinese site of Shangchen from Africa in about four years. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227082/original/file-20180711-27042-o0eyt6.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">A Hadza hunter with bow-and-arrow in Tanzania, 2013.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lake-eyasi-tanzania-february-18-unidentified-134540183?src=3iHm0pYi_FRzRzIPC1b9Ew-1-19">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>In reality, the journey from Africa to Asia (and beyond) wasn’t one great trek undertaken by particularly adventurous individuals searching for… treasure? fame? glory? Instead, it is likely that small groups moved only a little at a time as their families expanded, or necessary resources ran dry. </p>
<p>One can imagine the family matriarch and/or patriach saying to their extended family, something along the lines of, “Let us go to the next valley (or the next river) where there are plenty of fish/deer and it isn’t so crowded.”</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/rhino-fossil-rewrites-the-earliest-human-history-of-the-philippines-95879">Rhino fossil rewrites the earliest human history of the Philippines</a>
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<p>Perhaps on occasion there were a few irrepressible people who wanted to explore new lands and did cover significant distances in a single spurt. Perhaps they set up a new home far from their ancestors. </p>
<p>Certainly, such things have happened in recent times – Western Europeans turning up in Australia or North America, for example. </p>
<p>For the first humans moving out of Africa, there would not have been anyone to parlay with on arrival to new territories. Instead, they would have been entirely on their own when learning how to avoid new and exotic dangerous animals, identify and locate new foods and toolmaking supplies, and develop new ways to navigate. Each new landscape would have presented a significant challenge. Successfully setting up home or simply passing through without serious incident was no small feat. </p>
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Read more:
<a href="https://theconversation.com/chickens-tell-tale-of-human-migration-across-pacific-24461">Chickens tell tale of human migration across Pacific</a>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/YrOlE3x5JRs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Home on the Ocean. Colonisation of the Pacific and the last great human migration.</span></figcaption>
</figure>
<p>Humans are extremely flexible and adaptable to new environments. This trait has allowed a species that evolved in a hot grassy savanna to make its home in tropical rainforests, or the Arctic, or even on the ocean – as the <a href="http://www.abc.net.au/news/science/2016-10-04/dna-reveals-lapita-ancestors-of-pacific-islanders-came-from-asia/7893100">Lapita</a> people who colonised the Pacific did. </p>
<p>Ultimately, it allowed us to discover and colonise the entire globe as part of a multi-millenial human odyssey.</p><img src="https://counter.theconversation.com/content/99671/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Langley is an Australian Research Council DECRA Research Fellow at the Australian Research Centre for Human Evolution at Griffith University.</span></em></p>Conquer the globe? You bet we did – but when did it start? A new paper shows early humans made tools in China two million years ago.Michelle Langley, ARC DECRA Research Fellow, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/932312018-03-15T18:03:44Z2018-03-15T18:03:44ZThe revolution that wasn’t: African tools push back the origins of human technological innovation<figure><img src="https://images.theconversation.com/files/210524/original/file-20180315-104659-37uxmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">By about 320,000 years ago, humans in Kenya began using color pigments and manufacturing more sophisticated tools.</span> <span class="attribution"><span class="source">Human Origins Program, Smithsonian</span></span></figcaption></figure><p>Just 20 years ago, many archaeologists believed there was a “human revolution” 40,000-50,000 years ago during which modern behaviours such as symbolism, innovation and art suddenly arose. This was thought to have enabled a major shift in cognitive organisation and probably the advent of complex language. At the time, the earliest modern human fossils had been found in Africa and dated to some 100,000 years ago, leaving a gap between the emergence of anatomically modern humans and behaviourally modern humans.</p>
<p>This gap in the development suggested that we only achieved “modernity” <a href="http://www.chrisknight.co.uk/the-human-revolution/">as our species migrated out of Africa</a> and into the rest of the Old World. But this view is increasingly being challenged. Just weeks ago, we learned that Neanderthals <a href="https://theconversation.com/how-we-discovered-that-neanderthals-could-make-art-92127">could paint images</a>. Now, three new papers, published in Science, show that technologically advanced behaviours occurred much earlier than we thought in the African stone age.</p>
<p>Not all researchers supported the view that modernity arose outside of Africa. Writing at the turn of the millennium, archaeologists Sally McBrearty and Allison Brooks complained that <a href="https://www.researchgate.net/publication/12226275_The_Revolution_That_Wasn't_A_New_Interpretation_of_the_Origin_of_Modern_Human_Behavior">this view was Eurocentric</a> and brought about by a profound under-appreciation of the depth and complexity of the African archaeological record. They argued that components of the “human revolution” were to be found in the African Middle Stone Age some 280,000-50,000 years ago.</p>
<h2>The role of climate change</h2>
<p>Now, two decades later, Brooks and her colleagues have presented well-dated evidence from the Olorgesailie Basin in Kenya that places the evolution of some of these behaviours much further back in time. They highlight technological change at around 300,000 years ago that likely occurred in response to the effects of long-term, global environmental and climatic change. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210538/original/file-20180315-104639-1tfkgbo.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">
<figcaption>
<span class="caption">Olorgesailie Basin.</span>
<span class="attribution"><span class="source">Human Origins Program, Smithsonian</span></span>
</figcaption>
</figure>
<p>Around 800,000 years ago, the Olorgesailie Basin comprised a series of floodplains. Over the course of the next several hundred thousand years, <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aao2200">the climate changed</a> and the area developed into a vast arid grassland with massive turnover of prey mammal species as a consequence. </p>
<p>This would have made life difficult for early humans in the region by making food sources unpredictable. Human populations needed to adapt or go extinct. The crux of these papers is that hominin populations did not disappear – so at least some of them must have adapted technologically and culturally, with the environment driving greater mobility, information gathering and sharing, and innovation. </p>
<p>Based on excavations at five sites dating from 320,000 years ago, the team <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aao2216">found distinct differences</a> in the forms of stone tools compared to older deposits in the area – suggesting technological innovation had taken place. Older sites yielded large, bulky stone tools such as hand axes and cleavers. This technology is generally referred to as Acheulean (Early Stone Age).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210522/original/file-20180315-104645-1wdi27t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Older handaxes versus newer technology at the site.</span>
</figcaption>
</figure>
<p>In contrast, these sites at Olorgesailie contained much smaller, standardised pieces such as points and blades, some modified in a manner that made hafting possible. The team therefore <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aao2646">classified them</a> as Middle Stone Age industries. Many of the tools were made on obsidian (a volcanic glass) rather than rock. What’s more, chemical testing indictated that these raw materials came from 25-50 km away, and some from further afield. Some of these tools were made at the site and not brought in as finished items.</p>
<p>Obsidian wasn’t the only exotic material – they also discovered bright red ochre pigment displaying evidence of grinding and cut marks, which makes this among the oldest known pigments used to colour rocks in the archaeological record. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=840&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=840&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=840&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1056&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1056&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210536/original/file-20180315-104699-3f01bw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1056&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coloured rocks found at the site.</span>
<span class="attribution"><span class="source">Human Origins Program, Smithsonian</span></span>
</figcaption>
</figure>
<p>Together, the glass and ochre mark the earliest evidence for long-distance transport of raw materials in the East African record. </p>
<h2>Gap in the evidence</h2>
<p>Across Africa, the Middle Stone Age is characterised by the absence or rarity of large cutting tools and the presence of prepared core technologies for making sophisticated points and blades. Crucially, the transition between the African Early and Middle Stone Age occurred around the time that our own species, <em>Homo sapiens</em>, was evolving across the continent. </p>
<p>It might therefore be tempting to treat the appearance of the earliest Middle Stone Age technology as a cultural marker linked to the evolution and appearance of our own species – a smoking gun for evidence of the modern human mind. But it is probably too soon to jump to that conclusion.</p>
<p>Elsewhere across Africa, the association between Early and Middle Stone Age and pre- and fully-modern human fossils remains complex and confusing. Before 400,000 years ago, there are Early Stone Age sites which contain components such as blades and prepared cores. These are associated with archaic rather than modern human fossils such as at the <a href="https://en.wikipedia.org/wiki/Makapansgat">Cave of Hearths</a>. Conversely, we know that the production of Acheuelean large cutting tools by modern humans continued well into the period of the Middle Stone Age – such as at the 160,000-year-old site of <a href="http://news.bbc.co.uk/1/hi/sci/tech/2978800.stm">Herto</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210579/original/file-20180315-104699-18hhkcs.jpg?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">
<figcaption>
<span class="caption">African fossil sites from the Middle and earliest Late Pleistocene which have produced hominin fossils, often in association with stone tool assemblages.</span>
<span class="attribution"><span class="source">Lee Berger et al/eLife Journal</span></span>
</figcaption>
</figure>
<p>What is genuinely exciting about the discoveries in the Olorgesailie Basin is that we now know that one or more hominin groups were doing seemingly “modern” things at this critical time period. New tool forms and exotic materials require an understanding of space and time – bringing materials over great distances and passing on technological skills through successive generations. This suggests expanded social networks, transmission of information and technological innovation. </p>
<h2>Rethinking the revolution</h2>
<p>It does seem that the “human revolution” that made us modern never was – archaeological evidence for modern behaviours arose much earlier, starting in groups that predated our own species. Every criterion that has historically been used to differentiate modern humans from archaic humans – <a href="http://news.bbc.co.uk/1/hi/sci/tech/4166756.stm">culture</a>, <a href="https://www.theguardian.com/artanddesign/2018/feb/23/neanderthals-cave-art-spain-astounding-discovery-humbles-every-human">art</a>, <a href="https://www.sajs.co.za/article/view/3834">treatment of the dead</a>, <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119802">ornamentation</a> and <a href="http://johnhawks.net/weblog/archaeology/lower/trinil-shell-engraving-2014.html">abstract symbolism</a> – has much older examples.</p>
<p>What remains to be understood, however, is the relationship between complex behaviours and hominin species from 500,000 years to 160,000 years ago when <a href="https://elifesciences.org/articles/24234">many species of hominins</a> (not just modern humans) inhabited the African landscape. Gradual complex change is more difficult to interpret than revolution.</p><img src="https://counter.theconversation.com/content/93231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick Randolph-Quinney has worked extensively on Middle Pleistocene sites in South Africa. He is a scientist on the Rising Star team and co-author on papers describing the taphonomy and geological context of Homo naledi. He has co-directed palaeo-archaeological excavations in the Makapansgat Valley and region, including the Cave of Hearths. </span></em></p><p class="fine-print"><em><span>Anthony Sinclair 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>Scientists have discovered sophisticated tools in Kenya that are much older than expected.Patrick Randolph-Quinney, Reader/Associate Professor in Biological and Forensic Anthropology, University of Central LancashireAnthony Sinclair, Professor of Archaeological Theory and Method, University of LiverpoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/862322017-10-26T12:09:46Z2017-10-26T12:09:46ZThe theory that humans emerged in Africa is often questioned. That’s good for science<figure><img src="https://images.theconversation.com/files/191630/original/file-20171024-30571-t77ous.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Taung child (foreground) was the first of a long series of human ancestors discovered in Africa.</span> <span class="attribution"><span class="source">Julien Benoit</span></span></figcaption></figure><p>For nearly a century now the African root of human evolutionary theory has remained strong and unbowed. It is proved by a tremendous fossil record that documents the diversity of hominoids – apes and their relatives – <a href="https://www.nature.com/nature/journal/v548/n7666/full/nature23456.html">across the continent</a> through tens of millions of years. </p>
<p>Then, the human branch of the evolutionary tree (hominins) split only <a href="http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1001342">seven or eight million years ago</a> from our closest ape relatives, chimpanzees and gorillas. The oldest recorded hominin, whose skull was <a href="http://ai2-s2-pdfs.s3.amazonaws.com/4c7c/be464b918ce5e32868aa7aacb8688dea6c35.pdf">found in Chad</a> and has been nicknamed <a href="http://www.esrf.eu/news/general-old/general-2004/toumai/index_html">Toumaï</a>, is just a little younger than this. </p>
<p>Africa remained the unique centre of hominin evolution for approximately the next six million years. 1.8 million years ago, <em>Homo erectus</em> first <a href="http://www.sciencemag.org/news/2016/11/meet-frail-small-brained-people-who-first-trekked-out-africa">left the continent</a> – and today we’re everywhere.</p>
<p>Several recent pieces of research have questioned this established consensus. They have, either directly or in media articles about the work, suggested that humankind’s evolutionary tree should be re-rooted in Europe. This is the nature of science: a paradigm that cannot be questioned on a regular basis becomes a dogma. </p>
<p>So let’s examine these so-called “paradigm shifters” and see whether Africa should be stripped of the title of “cradle of humankind”.</p>
<h2>Teeth, footprints and a jawbone</h2>
<p>Two of the three studies done in Europe are based on evidence collected in Greece. The third was conducted in Germany. Two of them claim that their fossil finds could be older than the oldest hominin fossils found in Africa. </p>
<p>One of the Greek studies was <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0177127">based on</a> a toothless jawbone and a few teeth. The authors claim that they represent an 8 million year old hominin; older than Toumaï. </p>
<p>This research has been criticised – <a href="https://theconversation.com/theres-not-enough-evidence-to-back-the-claim-that-humans-originated-in-europe-78280">by me</a>, <a href="http://johnhawks.net/weblog/fossils/miocene/graecopithecus/graecopithecus-fuss-2017.html">among others</a>. As we’ve concluded, extraordinary claims require extraordinary evidence – and a jawbone plus a few teeth aren’t enough to counteract all the documentary proof of humans’ African origins.</p>
<p>Then came the second study. This was based on 5.7 million years old <a href="http://www.sciencedirect.com/science/article/pii/S001678781730113X">footprints</a>, again found in Greece. These appear to belong to <a href="https://theconversation.com/our-controversial-footprint-discovery-suggests-human-like-creatures-may-have-roamed-crete-nearly-6m-years-ago-82326">a bipedal animal</a>, but in the absence of bones, it is impossible to identify what made the tracks. Let’s admit that the track maker was a hominin, these tracks are younger that Toumaï so it is not impossible that they were made by an African species that went out of Africa earlier than <em>Homo erectus</em> did.</p>
<p>The most recent piece of research that seeks to stake Europe’s claim as human ancestors’ birthplace <a href="https://www.researchgate.net/publication/320518472_A_new_great_ape_with_startling_resemblances_to_African_members_of_the_hominin_tribe_excavated_from_the_Mid-Vallesian_Dinotheriensande_of_Eppelsheim_First_report_Hominoidea_Miocene_MN_9_Proto-Rhine_Riv">centres on two teeth</a>: a canine and a molar. This find was <a href="http://www.independent.co.uk/news/science/teeth-fossil-human-history-evolution-development-germany-rhine-mainz-archaeology-a8010506.html">greeted</a> with <a href="https://www.sciencealert.com/ancient-teeth-rewrite-human-history-9-7-million-year-old-mystery">some excitement</a> outside expert circles.</p>
<p>But scientists have responded sceptically. <a href="https://news.nationalgeographic.com/2017/10/ancient-teeth-found-germany-dont-rewrite-human-history-science/">Palaeoprimatologists</a> around the world have shown that the molar is not from a representative of the human family. Teeth in mammals, including humans, are very distinctive between species. The molar from Germany is simply too dissimilar from those of the earliest African hominins. It looks more like a molar belonging to <a href="https://www.ncbi.nlm.nih.gov/pubmed/15935440">Anapithecus</a>, a typically European species of fossil primates. These scientists have also argued that the “canine” is actually a fragment of a tooth from an antelope-like herbivorous animal.</p>
<p>In all three cases, the new evidence raised questions about the African origin of hominins and was critically evaluated. For now, these studies can’t be considered convincing enough to “<a href="http://www.news.com.au/technology/science/archaeology/discovery-of-97-millionyearold-teeth-could-rewrite-human-history/news-story/0850704c97ee57877c0dec312bc5ece1">rewrite human history</a>” – as some excited press releases claimed. But there is no doubt that more studies of the nature will follow, again and again.</p>
<p>The question is: should we consider these repeated attempts to move the root of the human evolutionary tree away from Africa a bad or a good thing?</p>
<h2>Questions are healthy</h2>
<p>The theory that humans emerged from Africa has only strengthened since 1924, which was when the first fossil remains of an <em>Australopithecus</em> – which became known as the <a href="https://www.nature.com/nature/ancestor/pdf/115195.pdf">Taung Child</a> – were found in South Africa. </p>
<p>The notion that Europe was actually the cradle of humankind, meanwhile, kept losing steam and crashed almost entirely after the notorious scientific hoax known as the “<a href="https://theconversation.com/a-new-twist-to-whodunnit-in-sciences-famous-piltdown-man-hoax-64470">Piltdown Man</a>” in the 1950s. </p>
<p>Nowadays, the African origin theory reigns supreme. That’s not to say that repeated attempts to disprove it are a bad thing. Scientifically speaking, it would be unhealthy for researchers to rest on their laurels. Every attempt to disprove the theory offers a chance to consider the evidence all over again, carefully looking for clues that might have been missed or new issues that might arise. </p>
<p>More “paradigm shifters” are bound to appear. But this does not imply that European researchers are trying to steal a march on Africa. All this emerging research is actually something worth getting excited about: it shows that science is on the move, constantly working to test and balance evidence. And that’s for the best.</p><img src="https://counter.theconversation.com/content/86232/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julien Benoit receives funding from The Claude Leon Foundation; PAST and its Scatterlings projects; the National Research Foundation of South Africa; and the DST-NRF Centre of Excellence in Palaeosciences (CoE in Palaeosciences).</span></em></p>Recent research suggests that humankind’s origins lay outside of Africa. This is the nature of science: a paradigm that cannot be questioned on a regular basis becomes a dogma.Julien Benoit, Postdoc in Vertebrate Palaeontology, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/788262017-06-07T20:13:02Z2017-06-07T20:13:02ZNew Moroccan fossils suggest humans lived and evolved across Africa 100,000 years earlier than we thought<figure><img src="https://images.theconversation.com/files/172591/original/file-20170607-3686-1yi8gtu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Just like us, but different: recently-discovered _Homo sapiens_ fossils have a modern face, but an ancient brain case. </span> <span class="attribution"><span class="source">Philipp Gunz, MPI EVA Leipzig</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>The earliest known existence of modern humans, or <em>Homo sapiens</em>, was previously dated to be around 200,000 years ago. It’s a view supported by genetic analysis and dated <em>Homo sapiens</em> fossils (<a href="http://www.nature.com/nature/journal/v433/n7027/abs/nature03258.html">Omo Kibish</a>, estimated age 195,000 years, and <a href="https://www.nature.com/nature/journal/v423/n6941/full/nature01669.html">Herto</a>, estimated age 160,000 years), both found in modern-day Ethiopia, East Africa.</p>
<p>But new research, published today in two Nature <a href="https://www.nature.com/articles/doi:10.1038/nature22336">papers</a>, offers a fresh perspective. The latest <a href="https://www.nature.com/articles/doi:10.1038/nature22335">studies</a> suggest that <em>Homo sapiens</em> spread across the entire African continent more than 100,000 years earlier than previously thought.</p>
<p>This evidence pushes back the origins of our species to 300,000 years ago, and supports the idea that important changes in our biology and behaviour had already taken place across most of Africa by that time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=237&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=237&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=237&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=298&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=298&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172587/original/file-20170607-3662-y7sn33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=298&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">View looking south of the Jebel Irhoud (Morocco) site. The remaining deposits and several people excavating them are visible in the centre. At the time the site was occupied by early hominins, it would have been a cave, but the covering rock and much sediment were removed by work at the site in the 1960s.</span>
<span class="attribution"><span class="source">Shannon McPherron, MPI EVA Leipzig</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Our work focused on samples collected at the archaeological site Jebel Irhoud in Morocco. It’s a place that is well known for hominin fossils – that is, bones from early humans – first excavated in the 1960s. </p>
<p>However, the interpretation of the first fossils and identification of their age was compromised previously, due to uncertainty about the geological dating of the sediment layers in which the remains had been found.</p>
<p>More than 40 years later, in 2004, an international team of scientists reopened the excavation. They discovered 16 new <em>Homo sapiens</em> fossils and a large number of Middle Stone Age artefacts. Now in 2017 we’re able to report on these remains thanks to improved dating techniques.</p>
<p>The new analysis proposes a revised version of the evolutionary history of modern humans that involves the entire African continent, and long before the “out-of-Africa” spread of <em>Homo sapiens</em> to other continents (dated at around 100,000 years ago).</p>
<p>Jebel Irhoud is the richest African Middle Stone Age site associated with the earliest known representative of our species. </p>
<h2>Bones with modern and ancient features</h2>
<p>The fossil remains excavated included numerous skulls and jawbones, long bones such as femur (from the leg) and humerus (from the arm), and teeth of several individuals. They reveal a mixture of modern human and more archaic, or ancient, features.</p>
<p>Of particular note is the slim, “gracile” face seen in living humans, which is also present in Jebel Irhoud specimens. Compared with the more robust face and elongated skull of Neanderthals or older hominins, the faces of Jebel Irhoud specimens are slender, relatively short, and sit under a rounder braincase (the part of the skull in which the brain sits).</p>
<p>However, while tomographic scans (which create 3D images through digital sectioning) reveal that the facial shape in the fossil samples is practically indistinguishable from humans nowadays, there are differences in the skull structure. In particular, the structure of the cranium, or skull bone, is different. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/F5Tkb5VkslQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Composite reconstruction of the earliest known <em>Homo sapiens</em> fossils from Jebel Irhoud (Morocco) based on micro computed tomographic scans of multiple original fossils. Dated to 300,000 years ago these early <em>Homo sapiens</em> already have a modern-looking face that falls within the variation of humans living today. However, the archaic-looking virtual imprint of the braincase (blue) indicates that brain shape, and possibly brain function, evolved within the <em>Homo sapiens</em> lineage. Credit: Philipp Gunz, MPI EVA Leipzig.</span></figcaption>
</figure>
<p>Compared with modern humans, in the Jebel Irhoud specimens we see a more elongated shape of the braincase, plus elongated temporal bones (on the sides of the skull, forming the temple), flatter parietal bones (along the sides and top of the skull) and different occipital shape (at the rear of the skull). This results in a longer and lower braincase. </p>
<p>Anatomically, this analysis places the 300,000-year-old Jebel Irhoud <em>Homo sapiens</em> somewhere between <em>Homo erectus</em> and African archaic Middle Pleistocene hominins. In this way it challenges the hypothesis that <em>Homo sapiens</em> derived from a later intermediate species that lead to the emergence of both the modern human and Neanderthal lineages.</p>
<p>These differences have implications for our understanding of <em>Homo sapiens</em> evolution. They suggest that our facial shape was established early in our history, whereas certain cognitive functions may have appeared later with the evolution of the <em>Homo sapiens</em> lineage and modifications of the braincase.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1030&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1030&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1030&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1294&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1294&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172588/original/file-20170607-3668-1r28zif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1294&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 first of our kind. Two views of the Irhoud 10 face. Several reconstructions of the second hominin face discovered at the Irhoud site can be proposed. All these reconstructions sit within the variability of extant, anatomically modern humans within the limits of anatomical constraints. Modern conditions for the facial skeleton were, therefore, already reached 300,000 years ago in the earliest forms of <em>Homo sapiens</em> known to date.</span>
<span class="attribution"><span class="source">Sarah Freidline, MPI EVA Leipzig</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>How we dated the Jebel Irhoud samples</h2>
<p>In addition to the fossils, stone artefacts found at the Jebel Irhoud site consisted of Middle Stone Age material of Levallois technology (a distinct method of creating stone tools), with a high proportion of retouched tools, especially pointed forms. </p>
<p>Materials from Jebel Irhoud were accurately dated using two distinct techniques.</p>
<p>Thermoluminescence (TL), which works by measuring the irradiation dose received from the surrounding sediment since the material was last exposed to heat or fire, was applied to the stone artefacts.</p>
<p>Techniques known as Coupled Uranium-Series and Electron Spin Resonance (together referred to as US-ESR) were applied to the fossil remains directly. By calculating the diffusion of natural elements (uranium and thorium) into the dental tissues as fossilisation occurred over time, combined with the amount of surrounding radiation from the sediment the enamel crystal has been exposed to, we are able to work out the burial time of the remains. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=506&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=506&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=506&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=636&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=636&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172589/original/file-20170607-3716-jg97im.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=636&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Photo of Irhoud 3 teeth embedded in the jawbone, and used for the US-ESR direct dating of the fossil. A fragment of enamel is carefully removed from the tooth using natural cracks to be measured in the spectrometer. After all measurements are complete, the piece of enamel can be replaced to its original position minimising the visual impact of the analyses and making the dating virtually non-destructive.</span>
<span class="attribution"><span class="source">Rainer Grün, RSES, ANU, Australia</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>While TL established clearly a chronology for the sediment layers which contained the hominin fossil remains, the US-ESR dates gave a direct age of one of the Jebel Irhoud jawbones (Irhoud 3 mandible). This was possible through new high-resolution radioactivity measurements of the geological context and important <a href="http://www.sciencedirect.com/science/article/pii/S1871101410000622">methodological improvements</a> which allowed us to understand the impact of irradiation onto the tooth enamel crystal structure.</p>
<p>Both dating of the jaw bone and the dating of the stone artefacts gave us an age of 300,000 years. </p>
<h2>A complex human journey</h2>
<p>The new find is consistent with a picture of complex, Africa-wide origin of <em>Homo sapiens</em>.</p>
<p>The observed skull shapes and calculated ages of the bones and tools have implications for interpreting other human-like fossils found in Africa. The enigmatic partial skull of <a href="http://www.tandfonline.com/doi/abs/10.1080/00359193709519748?journalCode=ttrs20">Florisbad</a> from South Africa is also a very important Middle Stone age sample, and presents a mix of modern and ancient features. </p>
<p>Whether Florisbad should be classified as <em>Homo heidelbergensis</em> or <em>Homo helmei</em> has been a subject of prolonged debate. But with the anatomical features observed in Jebel Irhoud specimen, Florisbad skull can be more securely described as an early <em>Homo sapiens</em> form.</p>
<p>This discovery is also interesting in light of the newly dated <em>Homo naledi</em> from <a href="https://elifesciences.org/articles/24231">South Africa</a>. This species, which survived until 250,000 years ago, overlaps in time with the Jebel Irhoud specimens. As <em>Homo naledi</em> represents a different branch of the genus <em>Homo</em> (not a direct ancestor to <em>Homo sapiens</em>), this is evidence that more archaic forms of hominins coexisted with the early representative of our species. </p>
<p>Similarly, <em>Homo erectus</em> <a href="https://www.britannica.com/place/Sale-paleoanthropological-site-Morocco">Salé</a> – also discovered in Morocco, not far from Jebel Irhoud – dates back to 250,000 years ago and might have coexisted with the early form of <em>Homo sapiens</em>, although the identification and age of the Salé specimen remains highly debated. </p>
<p>More than ever, as humans our complex evolutionary journey to end up as the lone surviving hominid species appears to be anything but linear. With African archaic Middle Pleistocene hominins overlapping in time with the Jebel Irhoud specimens, our discovery advocates for a complex African-wide evolutionary history of <em>Homo sapiens</em>. This new evidence adds more detail to the debate around the birthplace not only for our species, but also for the entire genus homo.</p>
<p>The famous drawing of a linear and simplistic evolution from ape-like individual morphing to an upright modern human is anything but accurate. </p>
<hr>
<p><em>This work was performed by teams of scientists from around the world, including those in Australia, Germany, USA, Morocco, France, UK and Italy.</em> </p>
<p><em>We acknowledge resources from <a href="http://www.smc.org.au/">AusSMC</a> in preparing this article.</em></p><img src="https://counter.theconversation.com/content/78826/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Renaud Joannes-Boyau receives funding from the Australian Research Council Discovery Grant (DP140100919). </span></em></p>New paired research papers have pushed back by 100,000 years the time frame in which humans (Homo sapiens) are thought to have lived in Africa.Renaud Joannes-Boyau, Senior research fellow, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/657452016-09-21T17:07:13Z2016-09-21T17:07:13ZGenetic studies reveal diversity of early human populations – and pin down when we left Africa<figure><img src="https://images.theconversation.com/files/138606/original/image-20160921-21711-9j6rw8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Aubrey Lynch, elder from the Wongatha Aboriginal language group, participated in one of the studies. </span> <span class="attribution"><span class="source">Preben Hjort, Mayday Film.</span></span></figcaption></figure><p>Humans are a success story like no other. We are now living in the “Anthropocene” age, meaning much of what we see around us has been made or influenced by people. Amazingly, all humans alive today – from the inhabitants of Tierra del Fuego on the southern tip of the Americas to the Sherpa in the Himalayas and the mountain tribes of Papua New Guinea – came from one common ancestor. </p>
<p>We know that our lineage arose in Africa and quickly spread to the four corners of the globe. But the details are murky. Was there just one population of early humans in Africa at the time? When exactly did we first leave the continent and was there just one exodus? Some scientists believe that all non-Africans today can trace their ancestry back to a single migrant population, while others argue that there were several different waves of migration out of Africa.</p>
<p>Now, three new studies mapping the genetic profiles of more than 200 populations across the world, published in <em>Nature</em>, have started to answer some of these questions. </p>
<h2>Out of Africa</h2>
<p>Humans initially spread out of Africa through the Middle East, ranging further north into Europe, east across Asia and south to Australasia. Later, they eventually spread north-east <a href="https://theconversation.com/first-americans-lived-on-land-bridge-for-thousands-of-years-genetics-study-suggests-23747">over the top of Beringia</a> into the Americas. We are now almost certain that on their way across the globe, <a href="http://www.nature.com/nature/journal/v524/n7564/full/nature14558.html">our ancestors interbred with</a> at least two archaic human species, the Neanderthals in Eurasia, and the <a href="http://www.nature.com/nature/journal/v468/n7327/abs/nature09710.html">Denisovans</a> in Asia. </p>
<p>Genetics has been invaluable in understanding this past. While <a href="http://science.sciencemag.org/content/239/4845/1263">hominin fossils hinted</a> that Africa was the birthplace of humanity, it was genetics that <a href="http://www.nature.com/nature/journal/v325/n6099/abs/325031a0.html">proved this to be so</a>. Patterns of genetic variation – how similar or different people’s DNA sequences are – have not only shown that most of the diversity we see in humans today is present within Africa, but also that there are fewer differences within populations the further you get from Africa. </p>
<p>These observations support the “Out of Africa” model; the idea that a small number of Africans moved out of the continent – taking a much reduced gene-pool with them. This genetic bottleneck, and the subsequent growth of non-African populations, meant that there was less genetic diversity to go round, and so there are fewer differences, on average, between the genomes of non-Africans compared to Africans.</p>
<p>When we scan two genomes to identify where these differences, or mutations, lie, we can estimate how long in the past those genomes split from each other. If two genomes share long stretches with no differences, it’s likely that their common ancestor was in the more recent past than the ancestor of two genomes with shorter shared stretches. By interrogating the distribution of mutations between African and non-African genomes, two of the papers just about agree that the genetic bottleneck caused by the migration out of Africa occurred roughly 60,000 years ago. This is also broadly in line with dating from archaeological investigations.</p>
<p>Their research also manages to settle a long-running debate about the structure of African populations at the beginning of the migration. Was the small group of humans who left Africa representative of the whole continent at that time, or had they split off from more southerly populations earlier?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">SGDP model of the relationships among diverse humans (select ancient samples are shown in red) that fits the data.</span>
<span class="attribution"><span class="source">Credit: Swapan Mallick, Mark Lipson and David Reich.</span></span>
</figcaption>
</figure>
<p>The Simons Genome Diversity Project compared the genomes of 142 worldwide populations, including 20 from across Africa. They <a href="http://nature.com/articles/doi:10.1038/nature18299">conclusively show</a> that modern African hunter-gatherer populations split off from the group that became non-Africans around 130,000 years ago and from West Africans around 90,000 years ago. This indicates that there was substantial substructure of populations in Africa prior to the wave of migration. A second study, led by Danish geneticist Eske Willersev, with far fewer African samples, used similar methods <a href="http://nature.com/articles/doi:10.1038/nature18964">to show</a> that divergence within Africa also started before the migration, around 125,000 years ago.</p>
<h2>More migrations?</h2>
<p>Following the move out of the continent, the pioneers must then have journeyed incredibly quickly to Australia. The Danish study, the most comprehensive analysis of Aboriginal Australian and Papuan genomes to date, is the first to really examine the position of Australia at the end of the migration.</p>
<p>They found that the ancestors of populations from “Sahul” – Tasmania, Australia and New Guinea – split from the common ancestor of Europeans and Asians 51,000-72,000 years ago. This is prior to their split from each other around 29,000-55,000 years ago, and almost immediately after the move out of Africa. This implies that the group of people who ended up in the Sahul split away from others almost as soon as the initial group left Africa. Substantial mixing with Denisovans is only seen in Sahulians, which is consistent with this early split.</p>
<p>Crucially, because the ancestors of modern-day Europeans and Asians hadn’t split in two at this point, we think that they must have still been somewhere in western Eurasia at this point. This means that there must have been a second migration from west Eurasia into east Asia later on. The Simons Genome Diversity Project study, by contrast, albeit with a far smaller sample of Sahulian genomes, found no evidence for such an early Sahulian split. It instead shows that the ancestors of East Asians and Sahulians split from western Eurasians before they split from each other, and therefore that Denisovan admixture occurred after the former split from each other.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=553&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=553&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=553&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=694&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=694&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=694&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A graphic representation of the interaction between modern and archaic human lines, showing traces of an early out of Africa (xOoA) expansion within the genome of modern Sahul populations.</span>
<span class="attribution"><span class="source">Dr Mait Metspalu at the Estonian Biocentre, Tartu, Estonia</span></span>
</figcaption>
</figure>
<p>Meanwhile, a third paper <a href="http://nature.com/articles/doi:10.1038/nature19792">proposes an earlier, “extra” migration</a> out of Africa, some 120,000 years ago. This migration is only visible in the genomes of a separate set of Sahulians sequenced as part of the Estonian Biocentre Human Genome Diversity Panel. Only around 2% per cent of these genomes can be traced to this earlier migration event, which implies that this wave can’t have many ancestors left in the present day. If true (the two other papers find little support for it), this suggests that there must have been a migration across Asia prior to the big one about 60,000 years ago, and that anatomically modern human populations left Africa earlier than many think.</p>
<p>Whatever the reality of the detail of the Out of Africa event, these studies provide some benchmarks for the timings of some of the key events. Importantly, they are also a huge resource of over 600 new and diverse human genomes that provide the genomics community with the opportunity for further understanding of the paths our ancestors took towards the Anthropocene.</p><img src="https://counter.theconversation.com/content/65745/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>George Busby 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>New research into how early humans spread across the world settles several long-running debates.George Busby, Research Associate in Statistical Genomics, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/506292015-11-20T04:36:01Z2015-11-20T04:36:01ZHow science has been abused through the ages to promote racism<figure><img src="https://images.theconversation.com/files/102325/original/image-20151118-14189-1mpkamn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientific evidence shows overwhelmingly that people across the world are genetic refugees from Africa.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Race in <a href="https://www.cbd.int/gti/taxonomy.shtml">human taxonomy</a> – the science of classifying organisms – has a long, disgraceful history. </p>
<p>Individuals have used race to divide and denigrate certain people while promoting their claims of superiority. Some of these individuals were, and are, respected in their time and their fields. They include philosopher and scientist <a href="http://global.britannica.com/biography/Robert-Boyle">Robert Boyle</a> and sociologists like <a href="https://books.google.co.za/books?id=IWDyVPi6pHgC&pg=PA35&lpg=PA35&dq=Hans+G%C3%BCnther+1891+%E2%80%93+1968&source=bl&ots=-UUgXQRqQO&sig=XAyokkxiY_wknDBWZyJ2GEvzsSU&hl=en&sa=X&ved=0CC0Q6AEwBGoVChMI5KapqZGcyQIVRlkUCh3E1AbV#v=onepage&q=Hans%20G%C3%BCnther%201891%20%E2%80%93%201968&f=false">Hans Günther</a>. Others who’ve been guilty include biologists like <a href="http://www.ucmp.berkeley.edu/history/haeckel.html">Ernst Haeckel</a> and historians such as <a href="http://global.britannica.com/biography/Henri-de-Boulainvilliers-comte-de-Saint-Saire">Henri de Boulainvilliers</a>. </p>
<p>What is the history of racially based classifications of humans? And does it have any scientific validity?</p>
<h2>Starting with Kant</h2>
<p>The eminent philosopher <a href="https://books.google.co.za/books?id=TE021UmMiAsC&pg=PA513&lpg=PA513&dq=Immanuel+Kant,+stupid,+trifling&source=bl&ots=FcD4KcVfoq&sig=-2rG2Iqv9Keq2adOa0Wb3PMV6u8&hl=en&sa=X&ved=0CEwQ6AEwCWoVChMIhq7_xpuXyQIVAW8UCh3t5QFM#v=onepage&q=Immanuel%20Kant%2C%20stupid%2C%20trifling&f=false">Immanuel Kant</a> was arguably the first “scientific racist”. He maintained that dark-skinned Africans were “vain and stupid”. He insisted that they were only capable of trifling feelings and were resistant to any form of education other than learning how to be enslaved.</p>
<p>By contrast, Kant maintained, light-skinned Caucasians were “active, acute, and adventurous”. </p>
<p>Renowned German anthropologist <a href="https://embryo.asu.edu/pages/johann-friedrich-blumenbach-1752-1840">Johann Blumenbach</a> used skull anatomy to divide humans into five races:</p>
<ul>
<li><p>Caucasians (Europe and western Asia);</p></li>
<li><p>Mongoloids (eastern Asia);</p></li>
<li><p>Malays (south-eastern Asia);</p></li>
<li><p>Negros (sub-Saharan Africa); and</p></li>
<li><p>Americans (North and South America).</p></li>
</ul>
<p>But he disagreed with the common view that humans from sub-Saharan Africa were inferior. Blumenbach’s “benign” racial categorisation persisted well into the 20th century.</p>
<p><a href="http://global.britannica.com/biography/Samuel-Morton">Samuel Morton</a> drew on refined, quantitative assessments of skull anatomy to provide further “scientific evidence”. He claimed that interracial intellectual variation is reflected by the interior volume of the skull, and that this justified the use of Blumenbach’s groupings to determine relative racial superiority. </p>
<p>He regarded the Caucasian as:</p>
<blockquote>
<p>… distinguished by the facility with which it attains the highest intellectual endowments</p>
</blockquote>
<p>and Africans as</p>
<blockquote>
<p>… joyous, flexible, and indolent; while the many nations which compose this race present a singular diversity of intellectual character, of which the far extreme is the lowest grade of humanity. </p>
</blockquote>
<p>“Scientific racism”“ was used to justify the ownership of <a href="http://abolition.e2bn.org/slavery_40.html">slaves</a>, as well as colonialism. It reached its pinnacle in eugenics, a "science” espoused by the British statistician and sociologist <a href="http://www.ncbi.nlm.nih.gov/pubmed/11700278">Francis Galton</a> at the end of the 19th century. </p>
<p>Eugenicists advocate the “improvement” of humanity by promoting reproduction between people with desired traits and reducing reproduction between people with less-desired traits. Eugenics featured in race-related legislation like Nazi Germany’s <a href="http://www.ushmm.org/outreach/en/article.php?ModuleId=10007695">Nuremberg Laws</a> and <a href="http://www.sahistory.org.za/article/apartheid-and-reactions-it">apartheid-era</a> South Africa’s edicts.</p>
<h2>Genetic evidence</h2>
<p>Genetic studies have examined “racial” variation from a molecular perspective. My early mentor <a href="http://sandwalk.blogspot.co.za/2008/07/good-science-writersrichard-lewontin.html">Richard Lewontin</a>, an evolutionary biologist from the University of Chicago, was a pioneer in this. His research suggested that 90% of modern human genetic diversity is found between individuals within populations. The tiny balance is due to variation between populations. </p>
<p>This view was confirmed by subsequent studies based on DNA by, among others, <a href="http://www.nature.com/ng/journal/v36/n11s/full/ng1435.html">Lynn B. Jorde and Stephen P. Wooding</a>. The DNA among all human populations is 99.5% similar. Populations of the geographically much more restricted chimpanzee exhibit more than four times the <a href="http://humanorigins.si.edu/evidence/genetics/skin-color/modern-human-diversity-genetics">genetic variation</a> that’s found between human populations. Chimpanzees are humans’ nearest living evolutionary “relative”.</p>
<p>Their research shows that when humans are studied from genetic or anatomical perspectives, the pattern that’s discovered is not diagnosable geographically discrete clusters. The norm is gradual, geographically uncorrelated variation in traits and genes. This is even true within peoples who are traditionally thought to be racially homogeneous. There is no evidence of evolutionarily significant racial variation in either genes or anatomy. </p>
<p>The exception is skin colour. Around 10% of the variance in skin colour occurs <a href="http://humanorigins.si.edu/evidence/genetics/skin-color/modern-human-diversity-skin-color">within groups</a> and about 90% between groups. People living near the equator have darker, more melanin-rich skin than those who live at higher latitudes. Darker skin is strongly selected for because it is a natural sunscreen that limits harmful effects of high ultraviolet rays. </p>
<p><a href="http://www.ucpress.edu/book.php?isbn=9780520275898">Recent genetic studies</a> indicate that skin colour may change radically within 100 generations because of natural selection.</p>
<h2>Genetic racism revived</h2>
<p>This overwhelming scientific evidence has not prevented recent studies based on <a href="http://ghr.nlm.nih.gov/glossary=allele">DNA allele frequencies</a> from claiming that there are as many as <a href="http://www.ncbi.nlm.nih.gov/pubmed/12493913">eight races of humans</a>. </p>
<p>British scientific journalist <a href="http://www.americanscientist.org/bookshelf/pub/a-troubling-tome">Nicholas Wade</a> used these studies to claim that natural selection between “races” produced differences in IQ, the efficacy of political institutions and countries’ levels of economic development. </p>
<p>These genetic studies are fundamentally flawed for three reasons: </p>
<ul>
<li><p>Taxonomic studies aimed at determining the validity of races should be based on characters. These are features that are invariant within populations. They should not be based on traits like eye colour and gene alleles, which vary within populations.</p></li>
<li><p>Samples used in the DNA-based studies mentioned above were “cherry picked” geographically to maximise differentiation between human populations, and </p></li>
<li><p>The DNA-based evolutionary racial “trees” were generated by a statistical technique that is designed to produce tree-like patterns which reflect average, not absolute, differences between sampled items. This technique formed the basis of an approach to the construction of evolutionary trees called “phenetics”. It has been decisively discredited and generally abandoned.</p></li>
</ul>
<h2>Evolutionary origins</h2>
<p>DNA and anatomy-based findings support the <a href="http://anthro.palomar.edu/homo/homo_2.htm">“Out of Africa” theory</a>. This holds that modern humans originated in Africa. Archaic African Homo erectus immigrated into Eurasia between 1.4 million to 1.6 million years ago. </p>
<p>About 90,000 to 92,000 years ago, a second form of humanity, modern H. sapiens, also emigrated out of Africa. This species replaced populations of Homo erectus already in the north. </p>
<p>Attempts to justify the scientific reality of human races warrant no further discussion. They cannot be used to assess racial “superiority”. “White” and other non-African people are in fact evolutionary refugees from Africa. After settling in Eurasia, it took only an evolutionary heartbeat for them to lose much of their epidermal melanin. </p>
<p>Dark-skinned humans outside of Africa are descended from migrants who “regained” their “blackness” in <a href="http://faculty.washington.edu/charles/562_f2011/Week%201/Jablonski%202004.pdf">equatorial regions</a> elsewhere.</p><img src="https://counter.theconversation.com/content/50629/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>While he was an academic at the University of Cape Town, his and his students' research was supported by South Africa's National Science Foundation, in some instance in collaboration with other international agencies.</span></em></p>Despite science refuting the existence of different human races, people have used “race” throughout history to divide and denigrate certain people while promoting their claims of superiority.Tim Crowe, Emeritus Professor, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.