Fossil DNA confirms interbreeding between humans and Neanderthals: 36,000-year-old skeleton reveals how the genes of the earliest inhabitants of Europe survived the Ice Age . Genome was taken from a 36,000-year-old skeleton found in Russia . DNA recovered shows the genes of the earliest inhabitants of Europe survived the Ice Age and shaped the modern population of the continent . Anthropologists from University of Cambridge and Copenhagen University say study shed light on interbreeding between Neanderthals and humans . They believe interbreeding occurred approximately 54,000 years ago . Experts say study reveals a framework to explore how humans responded to climate change, the Ice Age and encounters with other populations Anthropologists have long puzzled over how much contact Neanderthals had with modern humans and when this may have occured. Now, a genome taken from a 36,000-year-old skeleton has shed new light on the period of interbreeding between the two species. The study of DNA recovered from a fossil of one of the earliest known Europeans - a man who lived in Russia - shows that the genes of the earliest inhabitants of the continent survived the Ice Age, helping sow the seed for the modern-day population. The Kostenki genome revealed a small percentage of Neanderthal genes, confirming previous results that found Neanderthals and the first humans to leave Africa for Europe, briefly interbred. Even today, everyone with Eurasian ancestry - from Chinese to Scandinavian and North American - has a small element of Neanderthal DNA. But despite Western Eurasians going on to share the European landmass with Neanderthals for another 10,000 years, no further periods of interbreeding occurred, the study claims. Professor Robert Foley, of the University of Cambridge, questioned whether Neanderthal populations dwindled fast and how late modern humans encountered them. ‘We were originally surprised to discover there had been interbreeding. Now the question is, why so little?’ he said. ‘It’s an extraordinary finding that we don’t understand yet.’ Lead author Dr Eske Willerslev, an evolutionary biologist of the Centre for GeoGenetics at Copenhagen University, said the work revealed the complex web of population relationships in the past. He believes the study has revealed a firm framework with which to explore how humans responded to climate change, encounters with other populations, and the dynamic landscapes of the Ice Age, for the first time. Anthropologists now believe that Eurasians separated into at least three populations earlier than 36,000 years ago. All the decedents of Western Eurasians, East Asians and a mystery third lineage, developed the unique features of most non-African peoples - but not before some interbreeding with Neanderthals took place. The new study allows scientists to more accurately estimate when this occurred - around 54,000 years ago - before the Eurasian population began to separate. The ancient man’s complete genome is the second oldest modern human genome ever sequenced. By cross-referencing it with previous research, the team discovered a surprising unity running from the first modern humans in Europe. They believe that a ‘meta-population’ of hunter-gatherers with deep shared ancestry managed to survive through the last Ice Age and colonise the landmass of Europe for more than 30,000 years. While the communities within this population expanded, mixed and fragmented, this was a ‘reshuffling of the same genetic deck’, the researchers explained. European populations as a whole maintained the same genetic thread from their earliest establishment out of Africa until Middle Eastern populations arrived in the last 8,000 years, bringing with them agriculture and lighter skin colour. Marta Mirazon Lahr, from Cambridge University’s Leverhulme Centre for Human Evolutionary Studies, said: ‘That there was continuity from the earliest Upper Palaeolithic to the Mesolithic, across a major glaciation, is a great insight into the evolutionary processes underlying human success. ‘For 30,000 years, ice sheets came and went, at one point covering two-thirds of Europe. ‘Old cultures died and new ones emerged - such as the Aurignacian and the Grevettian - over thousands of years, and the hunter-gatherer populations ebbed and flowed. ‘But we now know that no new sets of genes are coming in: these changes in survival and cultural kit are overlaid on the same biological background. ‘It is only when farmers from the Near East arrived about 8,000 years ago that the structure of the European population changed significantly.’.
Posted on: Sun, 09 Nov 2014 16:59:25 +0000