Brown-eyed girl, isn't that a song??
September 4, 2012
The genome of a recently discovered branch of extinct humans known as the Denisovans that once interbred with us has been sequenced, scientists said today (Aug. 30).
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"This research will help [in] determining how it was that modern human populations came to expand dramatically in size as well as cultural complexity, while archaic humans eventually dwindled in numbers and became physically extinct," said researcher Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
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Although our species comprises the only humans left alive, our planet was once home to a variety of other human species. The Neanderthals were apparently our closest relatives, and the last of the other human lineages to vanish.
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To make the most of what little genetic material they had, the researchers developed a technique that unzipped the double strands of DNA in the bone, doubling the amount of DNA they could analyze. This enabled them to sequence each position in the genome about 30 times over, generating an extremely thorough genome sequence.
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Eight of these genetic changes have to do with brain function and brain development, "the connectivity in the brain of synapses between nerve cells function, and some of them have to do with genes that, for example, can cause autism when these genes are mutated," Pääbo added.
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The fact that differences are seen between modern humans and Denisovans in terms of autism-linked genes is especially interesting, because whole books have been written "suggesting that autism may affect sort of a trait in human cognition that is also crucial for modern humans, for how we put ourselves in the shoes of others, manipulate others, lie, develop politics and big societies and so on," Pääbo said.
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One possible explanation "is that the Denisovan gene flow into modern humans was mediated primarily by male Denisovans mixing with female modern humans," Reich said. "Another possible explanation is that actually there was natural selection to remove genetic material on the X chromosome that came from Denisovans once that entered the modern human population, perhaps because it caused problems for the people who carried it."
Genome of Mysterious Extinct Human Reveals Brown-Eyed Girl
[,,,]
"This research will help [in] determining how it was that modern human populations came to expand dramatically in size as well as cultural complexity, while archaic humans eventually dwindled in numbers and became physically extinct," said researcher Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
[,,,]
Although our species comprises the only humans left alive, our planet was once home to a variety of other human species. The Neanderthals were apparently our closest relatives, and the last of the other human lineages to vanish.
[,,,]
To make the most of what little genetic material they had, the researchers developed a technique that unzipped the double strands of DNA in the bone, doubling the amount of DNA they could analyze. This enabled them to sequence each position in the genome about 30 times over, generating an extremely thorough genome sequence.
[,,,]
Eight of these genetic changes have to do with brain function and brain development, "the connectivity in the brain of synapses between nerve cells function, and some of them have to do with genes that, for example, can cause autism when these genes are mutated," Pääbo added.
[,,,]
The fact that differences are seen between modern humans and Denisovans in terms of autism-linked genes is especially interesting, because whole books have been written "suggesting that autism may affect sort of a trait in human cognition that is also crucial for modern humans, for how we put ourselves in the shoes of others, manipulate others, lie, develop politics and big societies and so on," Pääbo said.
[,,,]
One possible explanation "is that the Denisovan gene flow into modern humans was mediated primarily by male Denisovans mixing with female modern humans," Reich said. "Another possible explanation is that actually there was natural selection to remove genetic material on the X chromosome that came from Denisovans once that entered the modern human population, perhaps because it caused problems for the people who carried it."
Genome of Mysterious Extinct Human Reveals Brown-Eyed Girl
Posted by Sane Spirit. Posted In : In the News