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DNA of girl from Denisova cave gives up genetic secrets | DNA of girl from Denisova cave gives up genetic secrets |
(about 11 hours later) | |
By Helen Briggs BBC News | By Helen Briggs BBC News |
The DNA of a cave girl who lived about 80,000 years ago has been analysed in remarkable detail. | The DNA of a cave girl who lived about 80,000 years ago has been analysed in remarkable detail. |
The picture of her genome is as accurate as that of modern day human genomes, and shows she had brown eyes, hair and skin. | The picture of her genome is as accurate as that of modern day human genomes, and shows she had brown eyes, hair and skin. |
The href="http://www.sciencemag.org/content/early/2012/08/31/science.1224344" >research in Science also sheds new light on the genetic differences between modern humans and their closest extinct relatives. | |
The cave dweller, a Denisovan, was a cousin of the Neanderthals. | The cave dweller, a Denisovan, was a cousin of the Neanderthals. |
Both groups of ancient humans died out about 30,000 years ago, but have left their mark in the gene pool of modern people. | Both groups of ancient humans died out about 30,000 years ago, but have left their mark in the gene pool of modern people. |
Shadowy past | Shadowy past |
The Denisovans have mysterious origins. They appear to have left little behind for palaeontologists save a tiny finger bone and a wisdom tooth found in Siberia's Denisova cave in 2010. | |
Though some researchers have proposed a possible link between the Denisovans and human fossils from China that have previously been difficult to classify. | |
A Russian scientist sent a fragment of the bone from Siberia to a team led by Svante Paabo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. | A Russian scientist sent a fragment of the bone from Siberia to a team led by Svante Paabo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. |
He thought it might belong to an early modern human, but the results came as a surprise. | He thought it might belong to an early modern human, but the results came as a surprise. |
DNA analysis revealed a human who was neither a Neanderthal nor a modern human but the first of a new group of ancient humans. | DNA analysis revealed a human who was neither a Neanderthal nor a modern human but the first of a new group of ancient humans. |
Gene catalogue | Gene catalogue |
Dr Paabo's team has now sequenced the genome of the Denisovan in much greater depth, using a new technique for studying ancient DNA. | Dr Paabo's team has now sequenced the genome of the Denisovan in much greater depth, using a new technique for studying ancient DNA. |
The quality of the genome sequence is similar to that seen in genome studies of modern day humans. | The quality of the genome sequence is similar to that seen in genome studies of modern day humans. |
"This is an extinct genome sequence of unprecedented accuracy," said Dr Matthias Meyer, the chief researcher on the study. | "This is an extinct genome sequence of unprecedented accuracy," said Dr Matthias Meyer, the chief researcher on the study. |
"For most of the genome we can even determine the differences between the two sets of chromosomes that the Denisovan girl inherited from her mother and father." | "For most of the genome we can even determine the differences between the two sets of chromosomes that the Denisovan girl inherited from her mother and father." |
The scientists compared the girl's genome with that of Neanderthals and 11 modern humans from around the world. | The scientists compared the girl's genome with that of Neanderthals and 11 modern humans from around the world. |
This allowed them to catalogue the gene changes that make modern humans different from the two groups of extinct humans that were their closest relatives. | This allowed them to catalogue the gene changes that make modern humans different from the two groups of extinct humans that were their closest relatives. |
They include changes to only a single DNA letter in several genes involved in the wiring of the brain and nervous system, as well as those that affect the eye and the skin. | They include changes to only a single DNA letter in several genes involved in the wiring of the brain and nervous system, as well as those that affect the eye and the skin. |
Dr Paabo said further investigation of changes in genes involved in connecting up the brain will be exciting to pursue. | Dr Paabo said further investigation of changes in genes involved in connecting up the brain will be exciting to pursue. |
He told BBC News: "To me the most exciting thing is having a good genome from our very closest extinct relatives which we can now compare ourselves to. | He told BBC News: "To me the most exciting thing is having a good genome from our very closest extinct relatives which we can now compare ourselves to. |
"It's a catalogue of what makes everyone on the planet unique compared with our closest extinct relatives." | "It's a catalogue of what makes everyone on the planet unique compared with our closest extinct relatives." |
The most detailed genetic analysis yet of the Denisovans also confirms that they bred with the ancestors of some people alive today, the researchers said. | The most detailed genetic analysis yet of the Denisovans also confirms that they bred with the ancestors of some people alive today, the researchers said. |
It shows that about 3% of the genes of people living today in Papua New Guinea come from Denisovans, with a trace of their DNA lingering in the Han and Dai people from mainland China. | |
The genetic variation of Denisovans was very low, suggesting that although they were found in large parts of Asia their population remained small. | The genetic variation of Denisovans was very low, suggesting that although they were found in large parts of Asia their population remained small. |
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