̽��ֱ�� of Cambridge - Leverhulme Centre for Human Evolutionary Studies

Prehistoric humans are likely to have formed mating networks to avoid inbreeding

tdk25 — Thu, 05 Oct 2017 18:00:13 +0000

̽��ֱ��study, reported in the journal Science, examined genetic information from the remains of anatomically modern humans who lived during the Upper Palaeolithic, a period when modern humans from Africa first colonised western Eurasia. ̽��ֱ��results suggest that people deliberately sought partners beyond their immediate family, and that they were probably connected to a wider network of groups from within which mates were chosen, in order to avoid becoming inbred.

This suggests that our distant ancestors are likely to have been aware of the dangers of inbreeding, and purposely avoided it at a surprisingly early stage in prehistory.

̽��ֱ��symbolism, complexity and time invested in the objects and jewellery found buried with the remains also suggests that it is possible that they developed rules, ceremonies and rituals to accompany the exchange of mates between groups, which perhaps foreshadowed modern marriage ceremonies, and may have been similar to those still practised by hunter-gatherer communities in parts of the world today.

̽��ֱ��study’s authors also hint that the early development of more complex mating systems may at least partly explain why anatomically modern humans proved successful while other species, such as Neanderthals, did not. However, more ancient genomic information from both early humans and Neanderthals is needed to test this idea.

̽��ֱ��research was carried out by an international team of academics, led by the ̽��ֱ�� of Cambridge, UK, and the ̽��ֱ�� of Copenhagen, Denmark. They sequenced the genomes of four individuals from Sunghir, a famous Upper Palaeolithic site in Russia, which is believed to have been inhabited about 34,000 years ago.

̽��ֱ��human fossils buried at Sunghir represent a rare and highly valuable source of information because, very unusually for finds from this period, the people buried there appear to have lived at the same time and were buried together. To the researchers’ surprise, however, these individuals were not closely related in genetic terms; at the very most, they were second cousins. This is true even in the case of two children who were buried head-to-head in the same grave.

Professor Eske Willerslev, a Fellow at St John’s College, Cambridge, Prince Philip Professor of Ecology and Evolution in the Department of Zoology, and a Professor at the ̽��ֱ�� of Copenhagen, was the senior author on the study. “What this means is that even people in the Upper Palaeolithic, who were living in tiny groups, understood the importance of avoiding inbreeding,” he said. “ ̽��ֱ��data that we have suggest that it was being purposely avoided.”

“This means that they must have developed a system for this purpose. If small hunter–gatherer bands were mixing at random, we would see much greater evidence of inbreeding than we have here.”

Early humans and other hominins such as Neanderthals appear to have lived in small family units. ̽��ֱ��small population size made inbreeding likely, but among anatomically modern humans it eventually ceased to be commonplace; when this happened, however, is unclear.

“Small family bands are likely to have interconnected with larger networks, facilitating the exchange of people between groups in order to maintain diversity,” Professor Martin Sikora, from the Centre for GeoGenetics at the ̽��ֱ�� of Copenhagen, said.

Sunghir contains the burials of one adult male and two younger individuals, accompanied by the symbolically-modified incomplete remains of another adult, as well as a spectacular array of grave goods. ̽��ֱ��researchers were able to sequence the complete genomes of the four individuals, all of whom were probably living on the site at the same time. These data were compared with information from a large number of both modern and ancient human genomes.

They found that the four individuals studied were genetically no closer than second cousins, while an adult femur filled with red ochre found in the children’s’ grave would have belonged to an individual no closer than great-great grandfather of the boys. “This goes against what many would have predicted,” Willerslev said. “I think many researchers had assumed that the people of Sunghir were very closely related, especially the two youngsters from the same grave.”

̽��ֱ��people at Sunghir may have been part of a network similar to that of modern day hunter-gatherers, such as Aboriginal Australians and some historical Native American societies. Like their Upper Palaeolithic ancestors, these people live in fairly small groups of around 25 people, but they are also less directly connected to a larger community of perhaps 200 people, within which there are rules governing with whom individuals can form partnerships.

“Most non-human primate societies are organised around single-sex kin where one of the sexes remains resident and the other migrates to another group, minimising inbreeding,” Professor Marta Mirazón Lahr, from the Leverhulme Centre for Human Evolutionary Studies at the ̽��ֱ�� of Cambridge, said. “At some point, early human societies changed their mating system into one in which a large number of the individuals that form small hunter-gatherer units are non-kin. ̽��ֱ��results from Sunghir show that Upper Palaeolithic human groups could use sophisticated cultural systems to sustain very small group sizes by embedding them in a wide social network of other groups.”

By comparison, genomic sequencing of a Neanderthal individual from the Altai Mountains who lived around 50,000 years ago indicates that inbreeding was not avoided. This leads the researchers to speculate that an early, systematic approach to preventing inbreeding may have helped anatomically modern humans to thrive, compared with other hominins.

This should be treated with caution, however: “We don’t know why the Altai Neanderthal groups were inbred,” Sikora said. “Maybe they were isolated and that was the only option; or maybe they really did fail to develop an available network of connections. We will need more genomic data of diverse Neanderthal populations to be sure.”

Willerslev also highlights a possible link with the unusual sophistication of the ornaments and cultural objects found at Sunghir. Group-specific cultural expressions may have been used to establish distinctions between bands of early humans, providing a means of identifying who to mate with and who to avoid as partners.

“ ̽��ֱ��ornamentation is incredible and there is no evidence of anything like that with Neanderthals and other archaic humans,” Willerslev added. “When you put the evidence together, it seems to be speaking to us about the really big questions; what made these people who they were as a species, and who we are as a result.”

̽��ֱ��research paper, Ancient genomes show social and reproductive behaviour of early Upper Paleolithic foragers, is published in the October 5 issue of Science.

Early humans seem to have recognised the dangers of inbreeding at least 34,000 years ago, and developed surprisingly sophisticated social and mating networks to avoid it, new research has found.

When you put the evidence together, it seems to be speaking to us about the really big questions; what made these people who they were as a species, and who we are as a result

Eske Willerslev

José-Manuel Benito Álvarez via Wikimedia Commons

Detail of one of the burials from Sunghir, in Russia.

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Celebrating 10 years of European research excellence

ag236 — Mon, 13 Mar 2017 12:40:43 +0000

When European government representatives met in Lisbon in the year 2000, and expressed an aspiration that Europe should become the world's leading knowledge economy by 2010, they agreed on the need to create a body to “fund and co-ordinate basic research at European level”.

This was the impetus underlying the creation, in 2007, of the European Research Council (ERC).

Ten years after its foundation, the ERC has become a European success story. It has supported some 6,500 projects through its prestigious grants, and has become a unique model for the fostering and funding of innovative academic research.

To mark the anniversary, events are being held across Europe during ERC Week, running from 13-19 March. At the ̽��ֱ�� of Cambridge, various recipients of ERC grants will be sharing their findings with a wide audience in talks scheduled as part of the Cambridge Science Festival.

̽��ֱ��McDonald Institute for Archaeological Research will be joining in ERC Week celebrations by hosting a conference on Thursday, 16 March.

On the same day, a reception for Cambridge recipients of ERC grants, attended by ERC president Prof. Jean-Pierre Bourguignon, will be held at the Fitzwilliam Museum, which is currently showing the ERC-supported exhibition, “Madonnas and Miracles: ̽��ֱ��Holy Home in Renaissance Italy”.

̽��ֱ��ERC supports outstanding researchers in all fields of science and scholarship. It awards three types of research awards (Starter, Consolidator, Advanced) through a competitive, peer-reviewed process that rewards excellence. Its focus on “frontier research” allows academics to develop innovative and far-reaching projects over five-year periods.

̽��ֱ��United Kingdom has been the largest recipient of ERC awards –between 2007 and 2015, it received 24% of all ERC funding.

To date, the ERC has supported 1524 projects by UK-based academics. Researchers at the ̽��ֱ�� of Cambridge have won 218 of those grants, in fields ranging from Astronomy to Zoology.

“What is special about an ERC grant?”, asks Dr Marta Mirazón Lahr, who was awarded an ERC Advanced Investigator Award for her project “IN-AFRICA”, which examines the evolution of modern humans in East Africa.

“An obvious side is that it’s a lot of money. But I think it’s more than just the money. Because it’s five years, the ERC grant allows you to get a group and build a real community around the project. It also allows you to explore things in greater depth.”

An ERC grant allowed Dr Debora Sijacki, at the Institute of Astronomy, to attract “a really competitive and international team, which otherwise would have been almost impossible to get.”

Being funded for a five-year period, she adds, “gives you time to expand and really tackle some of the major problems in astrophysics, rather than doing incremental research.”

It also allowed her access to facilities: “In my case, it was access to world-leading supercomputers. And without the ERC grant this would have been difficult.”

“Real progress in research is made when researchers can tackle big important questions," says Prof David Baulcombe, of the Department of Plant Sciences, the recipient of two ERC grants. " ̽��ֱ��ERC programme invites researchers to submit ambitious, blue-skies, imaginative proposals. There aren’t many others sources of funding that allow one to do that sort a thing.”

Dr Christos Lynteris, of the Centre for Research in the Arts, Humanities and Social Sciences (CRASSH), is the recipient of an ERC Starting Grant for his project “Visual representations of the third plague pandemic.

“An ERC is a unique opportunity," he says: “it fosters interdisciplinary work. It also fosters analytical tools and the creation of new methods.”

“It offers a great opportunity to work with other people, over a period of 5 years, which is something very unusual, and with quite a liberal framework, so you are able to change and shift your questions, to reformulate them. For me, it means freedom, above everything.”

For Prof. Ottoline Leyser, Director of the Sainsbury Laboratory, it is the “ERC ethos” and its “emphasis on taking things in new directions” that has made all the difference.

̽��ֱ��ERC values an innovative, risk-taking approach “in a way that conventional grant-funding schemes don’t –they usually want to see that slow build rather than the risky step into the unknown.”

Prof. Simon Goldhill, Director of CRASSH, was awarded an ERC Advanced Investigator Award for his project “Bible and Antiquity in 19th Century Culture”. It has given him “the unique opportunity to do a genuinely interdisciplinary collaborative project with the time and space it takes to make such interdisciplinarity work.”

“Most importantly,” he adds, “the financial model offered by this sort of project enables us to do work that is 15 or 20 years ahead of the rest of the world, and Britain and Europe are all the stronger for it.”

̽��ֱ��sentiment is echoed by Prof. Ruth Cameron, of the Department of Materials Science and Metallurgy. ̽��ֱ��impact of an ERC grant for her project “3D Engineered Environments for Regenerative Medicine” has, she says, “exceeded expectations”.

So what has the ERC ever done for us? Quite a lot, say Cambridge academics, as they mark the 10th anniversary of Europe’s premier research-funding body

̽��ֱ��financial model offered by this sort of project enables us to do work that is 15 or 20 years ahead of the rest of the world. Britain and Europe are all the stronger for it.

Prof. Simon Goldhill, CRASSH

Cambridge & the ERC: 10 years of research excellence

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Mapping the family tree of stars

ps748 — Mon, 20 Feb 2017 12:31:37 +0000

By studying chemical signatures found in the stars, they are piecing together these evolutionary trees looking at how the stars formed and how they are connected to each other. ̽��ֱ��signatures act as a proxy for DNA sequences. It’s akin to chemical tagging of stars and forms the basis of a discipline astronomers refer to as Galactic archaeology.

It was Charles Darwin, who, in 1859 published his revolutionary theory that all life forms are descended from one common ancestor. This theory has informed evolutionary biology ever since but it was a chance encounter between an astronomer and an biologist over dinner at King’s College in Cambridge that got the astronomer thinking about how it could be applied to stars in the Milky Way.

Writing in Monthly Notices of the Royal Astronomical Society, Dr Paula Jofré, of the ̽��ֱ�� of Cambridge’s Institute of Astronomy, describes how she set about creating a phylogenetic “tree of life” that connects a number of stars in the galaxy.

“ ̽��ֱ��use of algorithms to identify families of stars is a science that is constantly under development. Phylogenetic trees add an extra dimension to our endeavours which is why this approach is so special. ̽��ֱ��branches of the tree serve to inform us about the stars’ shared history“ she says.

̽��ֱ��team picked twenty-two stars, including the Sun, to study. ̽��ֱ��chemical elements have been carefully measured from data coming from ground-based high-resolution spectra taken with large telescopes located in the north of Chile. Once the families were identified using the chemical DNA, their evolution was studied with the help of their ages and kinematical properties obtained from the space mission Hipparcos, the precursor of Gaia, the spacecraft orbiting Earth that was launched by the European Space Agency and is almost halfway through a 5-year project to map the sky.

Stars are born from violent explosions in the gas clouds of the galaxy. Two stars with the same chemical compositions are likely to have been born in the same molecular cloud. Some live longer than the age of the Universe and serve as fossil records of the composition of the gas at the time they were formed. ̽��ֱ��oldest star in the sample analysed by the team is estimated to be almost ten billion years old, which is twice as old as the Sun. ̽��ֱ��youngest is 700 million years old.

In evolution, organisms are linked together by a pattern of descent with modification as they evolve. Stars are very different from living organisms, but they still have a history of shared descent as they are formed from gas clouds, and carry that history in their chemical structure. By applying the same phylogenetic methods that biologists use to trace descent in plants and animals it is possible to explore the ‘evolution’ of stars in the Galaxy.

“ ̽��ֱ��differences between stars and animals is immense, but they share the property of changing over time, and so both can be analysed by building trees of their history”, says Professor Robert Foley, of the Leverhulme Centre for Human Evolutionary Studies at Cambridge.

With an increasing number of datasets being made available from both Gaia and more advanced telescopes on the ground, and on-going and future large spectroscopic surveys, astronomers are moving closer to being able to assemble one tree that would connect all the stars in the Milky Way.

Paula Jofré et al. ‘Cosmic phylogeny: reconstructing the chemical history of the solar neighbourhood with an evolutionary tree’ is published by Monthly Notices of the Royal Astronomical Society. DOI 10.1093/mnras/stx075

Astronomers are borrowing principles applied in biology and archaeology to build a family tree of the stars in the galaxy.

̽��ֱ��branches of the tree serve to inform us about the stars' shared history

Dr Paula Jofré

Institute of Astronomy

Image showing family trees of stars in our Galaxy, including the Sun

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Sharpening our knowledge of prehistory on East Africa’s bone harpoons

tdk25 — Mon, 20 Feb 2017 09:00:20 +0000

East Africa is the epicentre of human evolution and its archaeological remains offer the potential to fill gaps in our understanding of early modern humans from their earliest origins, around 200,000 years ago, through to the most ‘recent’ prehistory of the last 10,000 years.

̽��ֱ��In Africa project, directed by Dr Marta Mirazón Lahr, co-founder of the Leverhulme Centre for Human Evolutionary Studies at the ̽��ֱ�� of Cambridge, is seeking to do exactly that. ̽��ֱ��group believes that, in East Africa, key ecological and cultural conditions converged, which allowed modern humans to evolve new behaviours and technologies to better exploit the natural resources that they found around them.

For the past five years, they has been working on the palaeoshores of Lake Turkana in Kenya, which has offered significant insights into how people there made use of aquatic resources such as fish or shellfish, something which is seen as a marker of human modernity.

Dr Alex Wilshaw, in Cambridge's Department of Biological Anthropology and a fellow of St John’s College, is a Research Associate on the project. “Looking at prehistoric tools and technology is a key way of exploring when and how the cultural and behavioural traits associated with modern humans were developed,” he explains.

“ ̽��ֱ��area around Lake Turkana is extraordinarily rich not just in fossils, but also in artefacts used to exploit the ecology of the area. In the case of aquatic resources from the lake, these artefacts are often harpoons or points made from bone. While previous archaeological projects have led to pockets of harpoon discovery, the extent of this project has afforded us the opportunity to collect unprecedented numbers of bone harpoons – to date, we have over 500 from 20 different sites.”

Mirazón Lahr and Wilshaw are now preparing a monograph cataloguing and describing the harpoons to give a clearer picture of the diversity that exists within the collection.

“Together, the harpoons have the potential to offer a spatial and temporal cross-section of the activities of early modern humans in the area and tell us something about functional and stylistic changes in technology,” Wilshaw says. “ ̽��ֱ��sites contain artefacts from groups who lived at different times and if we look at the harpoons in detail, their distinct styles show signs of variation among different populations and could offer clues about the appearance and disappearance of diverse groups as the lake levels rose and fell over time.”

̽��ֱ��harpoons range in date from around 13,000 years ago – late in the geological epoch known as the Pleistocene – to around 6,000 years ago, the middle of the current geological epoch known as the Holocene. ̽��ֱ��researchers used radiocarbon and other dating techniques on samples of shell and sediment surrounding the harpoons to place them in time.

While some of the harpoons were sharpened into elongated spears or barbed points, others look more like hooks. Some have been decorated and polished. “There is some discussion over what the harpoons were used for, but we think it is likely to have been fishing, rather than hunting of land animals, as they were all discovered on the lake edge,” Wilshaw explains. “ ̽��ֱ��harpoons would have been attached to a pole or haft and connected using twine or string which then enabled the hunter-fishers to spear their prey and then pull in their catch. There are some huge species of fish native to this area and some of the bigger and thicker harpoons may have been used to catch species like Nile Perch, which can grow up to two metres long. It is possible that the groups were using them to hunt hippo, which were also common in the area.”

̽��ֱ��research team focused their efforts on recovering remains from across an extensive landscape exhibiting the remnants of the lake edge and its surrounding flood plain. Many animal and human remains were fossilised and preserved in mud and sediment on the shores of the lake, but as the lake shrank and the environment became increasingly dry, the wind and rain eroded the surface and exposed the fossils.

This phenomenon led the group to the discovery not just of the bone harpoons, but also of many other prehistoric human remains and artefacts. Published last year in Nature, such fossilised bones protruding from the earth led to the remarkable discovery of the remains of a group of hunter gatherers who were brutally massacred around 10,000 years ago at the site of Nataruk – the earliest record of inter-group violence among prehistoric nomadic people.

̽��ֱ��researchers are hoping to win further funding to unlock more of the secrets of East Africa’s prehistoric harpoons.

“Some appear to have been carved from bone, some from ivory and others from horn, but we would like to do a more detailed analysis of what they were made out of and whether there was a preference for material,” adds Wilshaw. “Searching for patterns in functionality could reveal whether design and material varied for different prey and how creative the people were being with technology. Interestingly, some of the harpoons also look as if they have been polished and residue analysis could tell us what people were using to care for their tools”

̽��ֱ��In Africa project, which was funded by the European Research Council, aims to use its fossils and archaeological discoveries to enhance international awareness of the role of Africa in the evolution of human diversity.

“ ̽��ֱ��harpoons are the iconic remains of a people who have disappeared,” says Mirazón Lahr, “when they lived, Lake Turkana was much larger and the environment much richer. These discoveries allow us to track their lives, from when the lake rose as the ice age ended to the point where the lake shrank and desert conditions set in – bringing an end to the tradition that had lasted thousands of years and about which very little was previously known.”

Inset images from the In Africa project.

To keep up to date with the latest stories about Cambridge’s engagement with Africa, follow #CamAfrica on Twitter.

A project exploring the role of East Africa in the evolution of modern humans has amassed the largest and most diverse collection of prehistoric bone harpoons ever assembled from the area. ̽��ֱ��collection offers clues about the behaviour and technology of prehistoric hunter-gatherers.

"There are some huge species of fish native to this area and some of the bigger and thicker harpoons may have been used to catch species like Nile Perch, which can grow up to two metres long."

Alex Wilshaw

Harpoons discovered by the In Africa project

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Unprecedented study of Aboriginal Australians points to one shared Out of Africa migration for modern humans

tdk25 — Wed, 21 Sep 2016 18:00:19 +0000

̽��ֱ��first major genomic study of Aboriginal Australians ever undertaken has confirmed that all present-day non-African populations are descended from the same single wave of migrants, who left Africa around 72,000 years ago.

Researchers sequenced the complete genetic information of 83 Aboriginal Australians, as well as 25 Papuans from New Guinea, to produce a host of significant new findings about the origins of modern human populations. Their work is published alongside several other related papers in the journal Nature.

̽��ֱ��study, by an international team of academics, was carried out in close collaboration with elders and leaders from various Aboriginal Australian communities – some of whom are co-authors on the paper – as well as with various other organisations representing the participating groups.

Alongside the prevailing conclusion, that the overwhelming majority of the genomes of non-Africans alive today stem from one ancestral group of migrants who left Africa together, there are several other standout findings. These include:

Compelling evidence that Aboriginal Australians are descended directly from the first people to inhabit Australia – which is still the subject of periodic political dispute.
Evidence of an uncharacterised – and perhaps unknown – early human species which interbred with anatomically modern humans as they migrated through Asia.
Evidence that a mysterious dispersal from the northeastern part of Australia roughly 4,000 years ago contributed to the cultural links between Aboriginal groups today. These internal migrants defined the way in which people spoke and thought, but then disappeared from most of the continent, in a manner which the researchers describe as “ghost-like”.

̽��ֱ��study’s senior authors are from the ̽��ֱ�� of Cambridge, the Wellcome Trust Sanger Institute, the Universities of Copenhagen, Bern and Griffith ̽��ֱ�� Australia. Within Cambridge, members of the Leverhulme Centre for Evolutionary Studies also contributed to the research, in particular by helping to place the genetic data which the team gathered in the field within the context of wider evidence about early human population and migration patterns.

Professor Eske Willerslev, who holds posts at St John’s College, ̽��ֱ�� of Cambridge, the Sanger Institute and the ̽��ֱ�� of Copenhagen, initiated and led the research. He said: “ ̽��ֱ��study addresses a number of fundamental questions about human evolution – how many times did we leave Africa, when was Australia populated, and what is the diversity of people in and outside Australia?”

“Technologically and politically, it has not really been possible to answer those questions until now. We found evidence that there was only really one wave of humans who gave rise to all present-day non-Africans, including Australians.”

Anatomically modern humans are known to have left Africa approximately 72,000 years ago, eventually spreading across Asia and Europe. Outside Africa, Australia has one of the longest histories of continuous human occupation, dating back about 50,000 years.

Some researchers believe that this deep history indicates that Papuans and Australians stemmed from an earlier migration than the ancestors of Eurasian peoples; others that they split from Eurasian progenitors within Africa itself, and left the continent in a separate wave.

Until the present study, however, the only genetic evidence for Aboriginal Australians, which is needed to investigate these theories, came from one tuft of hair (taken from a long-since deceased individual), and two unidentified cell lines.

̽��ֱ��new research dramatically improves that picture. Working closely with community elders, representative organisations and the ethical board of Griffith ̽��ֱ��, Willerslev and colleagues obtained permission to sequence dozens of Aboriginal Australian genomes, using DNA extracted from saliva.

This was compared with existing genetic information about other populations. ̽��ֱ��researchers modelled the likely genetic impact of different human dispersals from Africa and towards Australia, looking for patterns that best matched the data they had acquired. Dr Marta Mirazon Lahr and Professor Robert Foley, both from the Leverhulme Centre, assisted in particular by analysing the likely correspondences between this newly-acquired genetic evidence and a wider framework of existing archaeological and anthropological evidence about early human population movements.

Dr Manjinder Sandhu, a senior author from the Sanger Institute and ̽��ֱ�� of Cambridge, said: “Our results suggest that, rather than having left in a separate wave, most of the genomes of Papuans and Aboriginal Australians can be traced back to a single ‘Out of Africa’ event which led to modern worldwide populations. There may have been other migrations, but the evidence so far points to one exit event.”

̽��ֱ��Papuan and Australian ancestors did, however, diverge early from the rest, around 58,000 years ago. By comparison, European and Asian ancestral groups only become distinct in the genetic record around 42,000 years ago.

̽��ֱ��study then traces the Papuan and Australian groups’ progress. Around 50,000 years ago they reached “Sahul” – a prehistoric supercontinent that originally united New Guinea, Australia and Tasmania, until these regions were separated by rising sea levels approximately 10,000 years ago.

̽��ֱ��researchers charted several further “divergences” in which various parts of the population broke off and became genetically isolated from others. Interestingly, Papuans and Aboriginal Australians appear to have diverged about 37,000 years ago – long before they became physically separated by water. ̽��ֱ��cause is unclear, but one reason may be the early flooding of the Carpentaria basin, which left Australia connected to New Guinea by a strip of land that may have been unfavourable for human habitation.

Once in Australia, the ancestors of today’s Aboriginal communities remained almost completely isolated from the rest of the world’s population until just a few thousand years ago, when they came into contact with some Asian populations, followed by European travellers in the 18th Century.

Indeed, by 31,000 years ago, most Aboriginal communities were genetically isolated from each other. This divergence was most likely caused by environmental barriers; in particular the evolution of an almost impassable central desert as the Australian continent dried out.

Assistant Professor Anna-Sapfo Malaspinas, from the Universities of Copenhagen and Bern, and a lead author, said: “ ̽��ֱ��genetic diversity among Aboriginal Australians is amazing. Because the continent has been populated for such a long time, we find that groups from south-western Australia are genetically more different from north-eastern Australia, than, for example, Native Americans are from Siberians.”

Two other major findings also emerged. First, the researchers were able to reappraise traces of DNA which come from an ancient, extinct human species and are found in Aboriginal Australians. These have traditionally been attributed to encounters with Denisovans – a group known from DNA samples found in Siberia.

In fact, the new study suggests that they were from a different, as-yet uncharacterised, species. “We don’t know who these people were, but they were a distant relative of Denisovans, and the Papuan/Australian ancestors probably encountered them close to Sahul,” Willerslev said.

Finally, the research also offers an intriguing new perspective on how Aboriginal culture itself developed, raising the possibility of a mysterious, internal migration 4,000 years ago.

About 90% of Aboriginal communities today speak languages belonging to the “Pama-Nyungan” linguistic family. ̽��ֱ��study finds that all of these people are descendants of the founding population which diverged from the Papuans 37,000 years ago, then diverged further into genetically isolated communities.

This, however, throws up a long-established paradox. Language experts are adamant that Pama-Nyungan languages are much younger, dating back 4,000 years, and coinciding with the appearance of new stone technologies in the archaeological record.

Scientists have long puzzled over how – if these communities were completely isolated from each other and the rest of the world – they ended up sharing a language family that is much younger? ̽��ֱ��traditional answer has been that there was a second migration into Australia 4,000 years ago, by people speaking this language.

But the new research finds no evidence of this. Instead, the team uncovered signs of a tiny gene flow, indicating a small population movement from north-east Australia across the continent, potentially at the time the Pama-Nyungan language and new stone tool technologies appeared.

These intrepid travellers, who must have braved forbidding environmental barriers, were small in number, but had a significant, sweeping impact on the continent’s culture. Mysteriously, however, the genetic evidence for them then disappears. In short, their influential language and culture survived – but they, as a distinctive group, did not.

“It’s a really weird scenario,” Willerslev said. “A few immigrants appear in different villages and communities around Australia. They change the way people speak and think; then they disappear, like ghosts. And people just carry on living in isolation the same way they always have. This may have happened for religious or cultural reasons that we can only speculate about. But in genetic terms, we have never seen anything like it before.”

̽��ֱ��paper, A Genomic History of Aboriginal Australia, is published in Nature. doi:10.1038/nature18299.

Inset images: Professor Eske Willerslev talking to Aboriginal elders in the Kalgoorlie area in southwestern Australia in 2012. (Photo credit: Preben Hjort, Mayday Film). / Map showing main findings from the paper. Credit: St John's College, Cambridge.

̽��ֱ��first significant investigation into the genomics of Aboriginal Australians has uncovered several major findings about early human populations. These include evidence of a single “Out of Africa” migration event, and of a previously unidentified, “ghost-like” population spread which provided a basis for the modern Aboriginal cultural landscape.

We found evidence that there was only really one wave of humans who gave rise to all present-day non-Africans, including Australians

Eske Willerslev

Preben Hjort, Magus Film

Aubrey Lynch, elder from the Wongatha Aboriginal language group, who participated in the study.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Opinion: No giant leap for mankind: why we’ve been looking at human evolution in the wrong way

Anonymous — Tue, 14 Jun 2016 13:21:45 +0000

Understanding exactly how and why humans evolved is clearly one of the most important goals in science. But despite a significant amount of research to date, these questions have remained a bit of a mystery. Of course, there is no shortage of theories – it has even been suggested that humans are just visiting aliens. However, most of the credible models tend to take something that is unique to humans – such as language – and show how all the other bits of being human derive from that.

But focusing on one dramatic change as an evolutionary driver in this way may not be the best approach to understanding our past. ̽��ֱ��question was discussed in a series of papers in Philosophical Transactions of the Royal Society B.

Hunting is a good example, as it is often used to explain human evolution. We eat far more meat than other primates – most of them are in fact entirely vegetarian. It has therefore been argued that meat was the high quality resource that allowed humans to evolve large and complex brains.

What’s more, it takes communication, cooperation and technology (those stone tools came in handy) to acquire it, so hunting could also explain a number of other typically human traits. Eating large animals also could also taught humans to share, leading to social cohesion and interdependence. Hunting is just one of many models that have been proposed to explain human uniqueness and cultural complexity – language, fire, cooking and grandmothers, who enhanced human success by investing in their daughters children instead of having more themselves.

Vince Smith/Flickr, CC BY-SA

̽��ֱ��problem with these theories is that they depend on evolution being a sort of one-step game, where one change produces a great leap forward, one from which other changes cascade. But the record does not support this. We split from our last common ancestor with the chimpanzees 5-6m years ago. But when we look at human ancestors between then and now, we do not find a single moment of dramatic change. Instead, it was cumulative – some 4m years ago we started walking upright on two legs, and about a million years later we started using stone tools. ̽��ֱ��size of our brains only started enlarging about 2m years ago.

Certainly there were periods that involved a more dynamic series of changes than others. For example, there was one at the beginning based on how hominins moved across the landscape, becoming bipedal and ranging over larger areas. Then about 2-3m years ago, there was another period of changes when brain size started to increase and childhood and adolescence periods started getting longer. This was coupled with boosts in technology and resource acquisition, such as hunting and gathering.

A final such period occurred in the last half million years, when cognitive changes associated with language, cooperation and cumulative culture – such as the development of more complex and composite technology, and the use of material culture for symbolic purposes – came to the fore. But even these periods, each lasting hundreds of thousands of years, were multi-event processes.

̽��ֱ��big picture

As far as we can tell, human evolution is like a mosaic of change, made up of many small steps, each of which adds a piece to what it is to be human. Only at the end do we see the full configuration, but had we stopped the clock at any point along that continuum, we would have seen a different mosaic. Human evolution is not one great transition, therefore, but many smaller ones.

Part of the problem in trying to see the big pattern of human evolution is that we look at it through the lens of the present – how we are today is the guide to how we were in the past. But the past was different in so many ways, and our extinct relatives show some surprising departures from what we expect when we base those expectations on ourselves.

̽��ֱ��remains of a Neanderthal wikimedia, CC BY-SA

Take body size. In the developed world, we are big, and sadly getting bigger in unhealthy ways. Better nutrition has led to increased body mass in many populations across the world. We also associate being large with being human, as it was thought that our ultimate ancestors, the australopithecines (living in Africa between about 4m and 2m years ago) were small, and that our own genus, Homo, marked a substantial increase in body size.

But that may not have been the case. In fact, nearly all the early, extinct species and subspecies of Homo were small, if not very small. ̽��ֱ��global average human body weight (combined sexes) now is over 60kg. No fossil hominin until the Neanderthals and modern humans reached an average of 50 kg, and most were below 40 kg – half the size of the average American male. Pygmy populations in Africa and Asia also weigh about 40kg, which means that most early and extinct hominins were pygmy sized. There are many advantages to large body size – such as resisting predators, access to larger prey – and the fact that our earliest ancestors did not become large tells us a lot about the energetic constraints under which they lived and reproduced.

We may picture our ancestors as rugged versions of ourselves, tall and strong, but they were not. We need to start thinking of them as creatures that were as unique as ourselves, but in different ways.

Understanding more about human evolution will depend on finding more fossils and applying more and more powerful scientific techniques. Ancient DNA, for example, is revealing extraordinary new details about our recent past. As important, however, will be using our greater knowledge of the overall pattern of human evolution, its tempo and mode, to inform us about the cumulative processes by which we became human, rather than expecting that with one great evolutionary bound, our hero was free.

Robert Foley, Professor of Human Evolution, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Robert Foley (Department of Archaeology and Anthropology) discusses the cumulative processes by which we became human.

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Australopithecus afarensis reconstruction

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Evidence of a prehistoric massacre extends the history of warfare

fpjl2 — Wed, 20 Jan 2016 17:35:21 +0000

̽��ֱ��fossilised bones of a group of prehistoric hunter-gatherers who were massacred around 10,000 years ago have been unearthed 30km west of Lake Turkana, Kenya, at a place called Nataruk.

Researchers from Cambridge ̽��ֱ��’s Leverhulme Centre for Human Evolutionary Studies (LCHES) found the partial remains of 27 individuals, including at least eight women and six children.

Twelve skeletons were in a relatively complete state, and ten of these showed clear signs of a violent death: including extreme blunt-force trauma to crania and cheekbones, broken hands, knees and ribs, arrow lesions to the neck, and stone projectile tips lodged in the skull and thorax of two men.

Several of the skeletons were found face down; most had severe cranial fractures. Among the in situ skeletons, at least five showed “sharp-force trauma”, some suggestive of arrow wounds. Four were discovered in a position indicating their hands had probably been bound, including a woman in the last stages of pregnancy. Foetal bones were uncovered.

̽��ֱ��bodies were not buried. Some had fallen into a lagoon that has long since dried; the bones preserved in sediment.

̽��ֱ��findings suggest these hunter-gatherers, perhaps members of an extended family, were attacked and killed by a rival group of prehistoric foragers. Researchers believe it is the earliest scientifically-dated historical evidence of human conflict – an ancient precursor to what we call warfare.

̽��ֱ��origins of warfare are controversial: whether the capacity for organised violence occurs deep in the evolutionary history of our species, or is a symptom of the idea of ownership that came with the settling of land and agriculture.

̽��ֱ��Nataruk massacre is the earliest record of inter-group violence among prehistoric hunter-gatherers who were largely nomadic. ̽��ֱ��only comparable evidence, discovered in Sudan in the 1960s, is undated, although often quoted as of similar age. It consists of cemetery burials, suggesting a settled lifestyle.

“ ̽��ֱ��deaths at Nataruk are testimony to the antiquity of inter-group violence and war,” said Dr Marta Mirazón Lahr, from Cambridge’s LCHES, who directs the ERC-funded IN-AFRICA Project and led the Nataruk study, published today in the journal Nature.

“These human remains record the intentional killing of a small band of foragers with no deliberate burial, and provide unique evidence that warfare was part of the repertoire of inter-group relations among some prehistoric hunter-gatherers,” she said.

̽��ֱ��site was first discovered in 2012. Following careful excavation, the researchers used radiocarbon and other dating techniques on the skeletons – as well as on samples of shell and sediment surrounding the remains – to place Nataruk in time. They estimate the event occurred between 9,500 to 10,500 years ago, around the start of the Holocene: the geological epoch that followed the last Ice Age.

Now scrubland, 10,000 years ago the area around Nataruk was a fertile lakeshore sustaining a substantial population of hunter-gatherers. ̽��ֱ��site would have been the edge of a lagoon near the shores of a much larger Lake Turkana, likely covered in marshland and bordered by forest and wooded corridors.

This lagoon-side location may have been an ideal place for prehistoric foragers to inhabit, with easy access to drinking water and fishing – and consequently, perhaps, a location coveted by others. ̽��ֱ��presence of pottery suggests the storage of foraged food.

“ ̽��ֱ��Nataruk massacre may have resulted from an attempt to seize resources – territory, women, children, food stored in pots – whose value was similar to those of later food-producing agricultural societies, among whom violent attacks on settlements became part of life,” said Mirazón Lahr.

“This would extend the history of the same underlying socio-economic conditions that characterise other instances of early warfare: a more settled, materially richer way of life. However, Nataruk may simply be evidence of a standard antagonistic response to an encounter between two social groups at that time.”

Click on images to enlarge

Antagonism between hunter-gatherer groups in recent history often resulted in men being killed, with women and children subsumed into the victorious group. At Nataruk, however, it seems few, if any, were spared.

Of the 27 individuals recorded, 21 were adults: eight males, eight females, and five unknown. Partial remains of six children were found co-mingled or in close proximity to the remains of four adult women and of two fragmentary adults of unknown sex.

No children were found near or with any of the men. All except one of the juvenile remains are children under the age of six; the exception is a young teenager, aged 12-15 years dentally, but whose bones are noticeably small for his or her age.

Ten skeletons show evidence of major lesions likely to have been immediately lethal. As well as five – possibly six – cases of trauma associated with arrow wounds, five cases of extreme blunt-force to the head can be seen, possibly caused by a wooden club. Other recorded traumas include fractured knees, hands and ribs.

Three artefacts were found within two of the bodies, likely the remains of arrow or spear tips. Two of these are made from obsidian: a black volcanic rock easily worked to razor-like sharpness. “Obsidian is rare in other late Stone Age sites of this area in West Turkana, which may suggest that the two groups confronted at Nataruk had different home ranges,” said Mirazón Lahr.

One adult male skeleton had an obsidian ‘bladelet’ still embedded in his skull. It didn’t perforate the bone, but another lesion suggests a second weapon did, crushing the entire right-front part of the head and face. “ ̽��ֱ��man appears to have been hit in the head by at least two projectiles and in the knees by a blunt instrument, falling face down into the lagoon’s shallow water,” said Mirazón Lahr.

Another adult male took two blows to the head – one above the right eye, the other on the left side of the skull – both crushing his skull at the point of impact, causing it to crack in different directions.

̽��ֱ��remains of a six-to-nine month-old foetus were recovered from within the abdominal cavity of one of the women, who was discovered in an unusual sitting position – her broken knees protruding from the earth were all Mirazón Lahr and colleagues could see when they found her. ̽��ֱ��position of the body suggests that her hands and feet may have been bound.

The Nataruk remains are now housed at the Turkana Basin Institute, Turkwell Station, for the National Museums of Kenya.

While we will never know why these people were so violently killed, Nataruk is one of the clearest cases of inter-group violence among prehistoric hunter-gatherers, says Mirazón Lahr, and evidence for the presence of small-scale warfare among foraging societies.

For study co-author Professor Robert Foley, also from Cambridge’s LCHES, the findings at Nataruk are an echo of human violence as ancient, perhaps, as the altruism that has led us to be the most cooperative species on the planet.

“I’ve no doubt it is in our biology to be aggressive and lethal, just as it is to be deeply caring and loving. A lot of what we understand about human evolutionary biology suggests these are two sides of the same coin,” Foley said.

Skeletal remains of a group of foragers massacred around 10,000 years ago on the shores of a lagoon is unique evidence of a violent encounter between clashing groups of ancient hunter-gatherers, and suggests the “presence of warfare” in late Stone Age foraging societies.

̽��ֱ��deaths at Nataruk are testimony to the antiquity of inter-group violence and war

Marta Mirazón Lahr

Left: Skull of a man found lying prone in the lagoons sediments. ̽��ֱ��skull has multiple lesions consistent with wounds from a blunt implement. Right: ̽��ֱ��skull in situ.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Opinion: Finding a hunter-gatherer massacre scene that may change history of human warfare

Anonymous — Tue, 19 Jan 2016 13:09:24 +0000

̽��ֱ��area surrounding Lake Turkana in Kenya was lush and fertile 10,000 years ago, with thousands of animals – including elephants, giraffes and zebras – roaming around alongside groups of hunter gatherers. But it also had a dark side. We have discovered the oldest known case of violence between two groups of hunter gatherers took place there, with ten excavated skeletons showing evidence of having been killed with both sharp and blunt weapons.

̽��ֱ��findings, published in Nature, are important because they challenge our understanding of the roots of conflict and suggest warfare may have a much older history than many researchers believe.

Shocking finding

Our journey started in 2012, when Pedro Ebeya, one of our Turkana field assistants, reported seeing fragments of human bones on the surface at Nataruk. Located just south of Lake Turkana, Nataruk is today a barren desert, but 10,000 years ago was a temporary camp set up by a band of hunter-gatherers next to a lagoon. I led a team of researchers, as part of the In-Africa project, which has been working in the area since 2009. We excavated the remains of 27 people – six young children, one teenager and 20 adults. Twelve of these – both men and women – were found as they had died, unburied, and later covered by the shallow water of the lagoon.

Ten of the 12 skeletons show lesions caused by violence to the parts of the body most commonly involved in cases of violence. These include one where the projectile was still embedded in the side of the skull; two cases of sharp-force trauma to the neck; seven cases of blunt and/or sharp-force trauma to the head; two cases of blunt-force trauma to the knees and one to the ribs. There were also two cases of fractures to the hands, possibly caused while parrying a blow.

There must have at least three types of weapons involved in these murders – projectiles (stoned-tipped as well as sharpened arrows), something similar to a club, and something close to a wooden handle with hafted sharp-stone blades that caused deep cuts. Two individuals have no lesions in the preserved parts of the skeleton, but the position of their hands suggests they may have been bound, including a young woman who was heavily pregnant at the time.

Me and my colleague, Justus Edung, during the excavations. Credit: Robert Foley

We dated the remains and the site to between 10,500 and 9,500 years ago, making them the earliest scientifically dated case of a conflict between two groups of hunter-gatherers. Stones in the weapons include obsidian, a rare stone in the Nataruk area, suggesting the attackers came from a different place.

̽��ֱ��(pre)history of warfare

Today we think of warfare, or inter-group conflict, as something that happens when one group of people wants the territory, resources or power held by another. But prehistoric societies were usually small groups of nomads moving from place to place – meaning they didn’t own land or have significant possessions. They typically didn’t have strong social hierarchies either. Therefore, many scholars have argued that warfare must have emerged after farming and more complex political systems arose.

Man with an obsidian bladelet embedded into the left side of his skull, and a projectile lesion (possibly of a sharpened arrow shaft) on the right side of the skull. Marta Mirazon Lahr

Naturuk therefore challenges our views about what the causes of conflict are. It is possible that human prehistoric societies simply responded antagonistically to chance encounters with another group. But this is not what seems to have happened at Nataruk. ̽��ֱ��group which attacked was carrying weapons that would not normally be carried while hunting and fishing. In addition, the lesions show that clubs of at least two sizes were used, making it likely that more than one of the attackers were carrying them.

̽��ֱ��fact that the attack combined long-distance weapons such as arrows and close-proximity weaponry such as clubs suggests they planned the attack. Also, there are other, but isolated, examples of violent trauma in this area from this period in time – one discovered in the 1970s about 20km north of Nataruk, and two discovered by our project at a nearby site. All three involved projectiles, one of the hallmarks of inter-group conflict. Two of the projectiles found embedded in the bones at Nataruk and in two of the other cases were made of obsidian. This tells us that such attacks happened multiple times, and were part of the life of the hunter-gatherer communities at the time.

So why were the people of Nataruk attacked? We have to conclude that they had valuable resources that were worth fighting for – water, meat, fish, nuts, or indeed women and children. This suggests that two of the conditions associated with warfare among settled societies – territory and resources – were probably common among these hunter-gatherers, and that we have underestimated their role so far.

Evolution is about survival, and our species is no different from others in this respect. ̽��ֱ��injuries suffered by the people of Nataruk are merciless and shocking, but no different from those suffered in wars throughout much of our history – sadly even today. It may be human nature, but we should not forget that extraordinary acts of altruism, compassion and caring are also unique parts of who we are.

Marta Mirazon Lahr, Reader in Human Evolutionary Biology & Director of the Duckworth Collection, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Marta Mirazon Lahr (Leverhulme Centre for Human Evolutionary Studies) discusses the discovery, made by her and her team, of the oldest known case of violence between two groups of hunter gatherers.

Image by Marta Mirazon Lahr, enhanced by Fabio Lahr

Skull of a man with multiple lesions on the side, probably caused by a club.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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