Posted on February 16, 2014 by Deus Nexus Leave a comment
Reposted from: Ancient Origins | By April Holloway
A new study presented to the Royal Society meeting on ancient DNA in London last week has revealed a dramatic finding – the genome of one of our ancient ancestors, the Denisovans, contains a segment of DNA that seems to have come from another species that is currently unknown to science. The discovery suggests that there was rampant interbreeding between ancient human species in Europe and Asia more than 30,000 years ago. But, far more significant was the finding that they also mated with a mystery species from Asia – one that is neither human nor Neanderthal.
Scientists launched into a flurry of discussion and debate upon hearing the study results and immediately began speculating about what this unknown species could be. Some have suggested that a group may have branched off to Asia from the Homo heidelbernensis, who resided in Africa about half a million years ago. They are believed to be the ancestors of Europe’s Neanderthals.
However others, such as Chris Stringer, a paleoanthropologist at the London Natural History Museum, admitted that they “don’t have the faintest idea” what the mystery species could be.
Traces of the unknown new genome were detected in two teeth and a finger bone of a Denisovan, which was discovered in a Siberian cave. There is not much data available about the appearance of Denisovans due to lack of their fossils’ availability, but the geneticists and researchers succeeded in arranging their entire genome very precisely.
“What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world – that there were many hominid populations,” Mark Thomas, an evolutionary geneticist at University College London.
The question is now: who were these mystery people that the Denisovans were breeding with?
Mystery humans spiced up ancients’ sex lives
Genome analysis suggests there was interbreeding between modern humans, Neanderthals, Denisovans and an unknown archaic population.
Reposted from: nature.com | by Ewen Callaway
Updated genome sequences from two extinct relatives of modern humans suggest that these ‘archaic’ groups bred with humans and with each other more extensively than was previously known.
The ancient genomes, one from a Neanderthal and one from a member of an archaic human group called the Denisovans, were presented on 18 November at a meeting on ancient DNA at the Royal Society in London. The results suggest that interbreeding went on between the members of several ancient human-like groups in Europe and Asia more than 30,000 years ago, including an as-yet-unknown human ancestor from Asia.
“What it begins to suggest is that we’re looking at a Lord of the Rings-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work.
The first published Neanderthal1 and Denisovan2 genome sequences revolutionized the study of ancient human history, not least because they showed that these groups bred with anatomically modern humans, contributing to the genetic diversity of many people alive today.
All modern humans whose ancestry originates outside of Africa owe about 2% of their genome to Neanderthals. Certain populations living in Oceania, such as Papua New Guineans and Australian Aboriginals, share about 4% of their DNA with Denisovans, members of a group named after a cave in the Altai Mountains in Siberia, Russia, where they were discovered. The cave contains remains deposited between 30,000 and 50,000 years ago.
At the meeting, however, David Reich, an evolutionary geneticist at Harvard Medical School in Boston, Massachusetts, who worked on those studies, said that the conclusions were based on low-quality genome sequences, riddled with errors and full of gaps. His team, along with collaborator Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has now produced much more complete versions of the Denisovan and Neanderthal genomes — matching the quality of contemporary human genomes. These high-quality Denisovan and Neanderthal sequences are both based on bones from the Denisova Cave.
The Denisovan genome indicates that the population got around: Reich said at the meeting that as well as interbreeding with the ancestors of Oceanians, they also bred with Neanderthals and the ancestors of modern humans in China and other parts of East Asia. Most surprisingly, Reich said, the genomes indicate that Denisovans interbred with yet another extinct population of archaic humans that lived in Asia more than 30,000 years ago — one that is neither human nor Neanderthal.
The meeting was abuzz with conjecture about the identity of this unknown population of humans. “We don’t have the faintest idea,” says Chris Stringer, a paleoanthropologist at the Natural History Museum in London, who was not involved in the work. He speculates that the population could be related toHomo heidelbergensis, a species that left Africa around half a million years ago and later gave rise to Neanderthals in Europe. “Perhaps it lived on in Asia as well,” says Stringer.
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