Tooth, finger contain DNA of long-lost human relative
By Randy Boswell, Postmedia News December 23, 2010
A tooth and a finger bone found in a Siberian cave have led to a startling discovery about a previously unknown branch of the human family, according to a landmark study published Wednesday by an international team of researchers, including a B.C. scientist.
University of B.C. anthropologist Michael Richards is among 28 co-authors of a paper in the journal Nature that details the identification of the long-lost species of early humans -- the "Denisovans" -- that disappeared about 30,000 years ago but left a distinctive genetic legacy seen today in certain island populations of Southeast Asia.
Named for the Altai Mountains cave in southern Russia where the remains were found, the Denisovan tooth and finger, which came from two different members of the species, yielded surprisingly high-quality DNA that allowed scientists to discern the outlines of the Denisovans's evolutionary history from the time they branched away from their Neanderthal "sister group" hundreds of thousands of years ago and headed toward eastern Asia.
"There was probably an ancestral group that left Africa between 300,000 and 400,000 years ago and quickly diverged, with one branch becoming the Neanderthals who spread into Europe and the other branch moving east and becoming Denisovans," according to a summary of the Nature study by the University of California, where co-author Richard Green, a biomolecular engineer, helped analyze the Denisovans's DNA.
"When modern humans left Africa about 70,000 to 80,000 years ago, they first encountered the Neanderthals, an interaction that left traces of Neanderthal DNA scattered through the genomes of all non-Africans," the summary states.
"One group of humans later came in contact with Denisovans, leaving traces of Denisovan DNA in the genomes of humans who settled in Melanesia."
The Melanesians exhibiting traces of Denisovan DNA were from New Guinea and Bougainville, islands north of Australia.
"Instead of the clean story we used to have of modern humans migrating out of Africa and replacing Neanderthals, we now see these very intertwined storylines with more players and more interactions than we knew of before," said Green.
He added that "it is almost miraculous how well-preserved the DNA is."
Instead of the clean story we used to have of modern humans migrating out of Africa and replacing Neanderthals, we now see these very intertwined storylines with more players and more interactions than we knew of before.
Richards and Green biomolecular engineer and co-author of Nature paper with the Max Planck Institute for Evolutionary Anthropology in Germany and lead author of the Nature study, co-authored a paper earlier this year that revealed the discovery of the finger bone and raised the likelihood that a new human cousin had been found.
The subsequent DNA analysis, in combination with evidence gleaned from the tooth, has solidified the identification of the Denisovan branch of the human family tree.
Richards, who also holds a position at the Max Planck Institute, could not be reached Wednesday. But his UBC web-site says his research focuses on "the expansion of modern humans into Eurasia" and "reconstructing past human and animal diets and migrations."
SCIENCE NEWS UPDATED 24/7 at vancouversun.com/technology/science
University of B.C. anthropologist Michael Richards is among 28 co-authors of a paper in the journal Nature that details the identification of the long-lost species of early humans -- the "Denisovans" -- that disappeared about 30,000 years ago but left a distinctive genetic legacy seen today in certain island populations of Southeast Asia.
Named for the Altai Mountains cave in southern Russia where the remains were found, the Denisovan tooth and finger, which came from two different members of the species, yielded surprisingly high-quality DNA that allowed scientists to discern the outlines of the Denisovans's evolutionary history from the time they branched away from their Neanderthal "sister group" hundreds of thousands of years ago and headed toward eastern Asia.
"There was probably an ancestral group that left Africa between 300,000 and 400,000 years ago and quickly diverged, with one branch becoming the Neanderthals who spread into Europe and the other branch moving east and becoming Denisovans," according to a summary of the Nature study by the University of California, where co-author Richard Green, a biomolecular engineer, helped analyze the Denisovans's DNA.
"When modern humans left Africa about 70,000 to 80,000 years ago, they first encountered the Neanderthals, an interaction that left traces of Neanderthal DNA scattered through the genomes of all non-Africans," the summary states.
"One group of humans later came in contact with Denisovans, leaving traces of Denisovan DNA in the genomes of humans who settled in Melanesia."
The Melanesians exhibiting traces of Denisovan DNA were from New Guinea and Bougainville, islands north of Australia.
"Instead of the clean story we used to have of modern humans migrating out of Africa and replacing Neanderthals, we now see these very intertwined storylines with more players and more interactions than we knew of before," said Green.
He added that "it is almost miraculous how well-preserved the DNA is."
Instead of the clean story we used to have of modern humans migrating out of Africa and replacing Neanderthals, we now see these very intertwined storylines with more players and more interactions than we knew of before.
Richards and Green biomolecular engineer and co-author of Nature paper with the Max Planck Institute for Evolutionary Anthropology in Germany and lead author of the Nature study, co-authored a paper earlier this year that revealed the discovery of the finger bone and raised the likelihood that a new human cousin had been found.
The subsequent DNA analysis, in combination with evidence gleaned from the tooth, has solidified the identification of the Denisovan branch of the human family tree.
Richards, who also holds a position at the Max Planck Institute, could not be reached Wednesday. But his UBC web-site says his research focuses on "the expansion of modern humans into Eurasia" and "reconstructing past human and animal diets and migrations."
SCIENCE NEWS UPDATED 24/7 at vancouversun.com/technology/science
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