This one is one of millions, just announced
by Magnifico
Wed Dec 22, 2010
The human family just got a tad more diverse in research published in Nature today. The fossil genome of the Denisovans reveals ancestral link to the present-day inhabitants of Papua New Guinea and islands northeast of Australia, Nature News reports. The Denisovans lived in Asia about 400,000 to 50,000 years ago and are the cousins or 'sister group' of the Neanderthals.
A fossilized 'pinky' finger bone from a girl who lived about 30,000 to 50,000 years ago gave up a genome sequence to scientists working at the Max Planck Institute for Evolutionary Anthropology in Liepzig, Germany. From that sequence, geneticist Svante Pääbo "and his colleagues could tell little, except that the individual, now known to be female, was part of a population long diverged from humans and Neanderthals."
Whoa! Human evolution just got a little more complicated.
Her approximately 3-billion-letter nuclear genome... now provides a more telling glimpse into this mysterious group. It also raises previously unimagined questions about its history and relationship to Neanderthals and humans. "The whole story is incredible. It's like a surprising Christmas present," says Carles Lalueza Fox, a palaeogeneticist at Pompeu Fabra University in Barcelona, Spain, who was not involved in the research.
"An analysis of this ancient DNA... reveals that genomes of people from New Guinea contain 4.8 percent Denisovan DNA," the New York Times reports of the finding."
The girl's finger bone and a large molar tooth were discovered in the Denisova cave in the Altai mountains of southern Siberia in 2008. "The adult tooth was too large to belong to a modern human or Neanderthal", adds The Guardian. Anatoli Derevianko of the Russian Academy of Sciences and his colleagues then sent the finds to Pääbo to have its genome sequenced. After initial tests, the discovery that the "Denisova DNA was markedly different from that of either humans or Neanderthals" came as a complete surprise to Pääbo and his team.
"It was a great shock to us that it was distinct from those groups," Dr. Pääbo said in an interview and quoted by the NY Times.
After sequencing the entire genome, they shared the data with two American teams working at Harvard Medical School and the Broad Institute. "The Massachusetts scientists concluded that the finger bone belonged to a hominin branch that split from the ancestors of Neanderthals roughly 400,000 years ago."
Nick Patterson, a Broad Institute geneticist, was among the researchers that used the Denisovan genome to hunt for evidence of interbreeding. "To his astonishment, a sizable chunk of the Denisova genome resembled parts of the New Guinea DNA."
"The correct reaction when you get a surprising result is, ‘What am I doing wrong?’ " said Dr. Patterson. To see if the result was an error, he and his colleagues sequenced the genomes of seven more people, including another individual from New Guinea and one from the neighboring island of Bougainville. But even in the new analysis, the Denisovan DNA still turned up in the New Guinea and Bougainville genomes.
"It is almost miraculous how well preserved the DNA is," said Richard Green, of the University of California in Santa Cruz, a member of Pääbo's team, in the Sydney Morning Herald. The discovery that some modern humans share Denisovan DNA means human evolutionary history is even more complicated than once though.
"We now see these very intertwined story lines with more players and more interactions than we knew of before," Green said.
How Denisovan DNA found in Siberia could have wound up in Papua New Guinea is a mystery, National Geographic reports.
"We don't think the Denisovans went to Papua New Guinea," located at the northwestern edge of the Pacific region called Melanesia, explained study co-author Bence Viola, an anthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
"We think the Denisovan population inhabited most of eastern Eurasia in the same way that Neanderthals inhabited most of western Eurasia," Viola said. "Our idea is that the ancestors of Melanesians met the Denisovans in Southeast Asia and interbred, and the ancestors of Melanesians then moved on to Papua New Guinea."
Only a few "fleeting encounters" between Denisovans and modern human ancestors could have introduced Denisovan genome into our DNA, BBC News reports.
"It could be just 50 Denisovans interbreeding with a thousand modern humans. That would be enough to produce this 5% of those archaic genes being transferred," said Chris Stringer of the Natural History Museum in London, who was not involved in the research.
"So the impact is there but the number of interbreeding events might have been quite small and quite rare," he said.
The Guardian adds:
Pääbo decided not to name the group a new human species to avoid academic fights over whether they represent a separate species or not. "Even for Neanderthals, where we have more remains than from any other group, palaeontologists can still not agree on whether they are a species or a subspecies. It is a sterile academic discussion because there will never be a resolution and I don't want to get into that," he said.
The link between the Denisovans and modern Melanesians was completely unexpected and shows the Denisovans must have lived far outside Siberia, Pääbo added. "This tells us that modern humans had babies not only with Neanderthals, but with the Denisovans too, and those kids became incorporated in human ancestral groups and contributed to us today. That is fascinating. There are two archaic groups that live on in us today and probably more," Pääbo said.
Earlier this year in May, Pääbo and his colleagues published the complete Neanderthal genome, which found evidence that Neanderthals mated with some modern humans.
With humans getting it on with Neanderthals and their cousins the Denisovans, "the ice-age world is starting to look cosmopolitan."
In my opinion, the biggest enemy religion has is not us Agnostics or Liberal-Progressives…no sir, it is science. Science keeps slapping them in the face and slam dunking all these scientific proofs of the validity of EVOLUTION. Of course, the Evangelicals will never accept science as a rebuttal because they have “FAITH” and it can’t be proven or put side by side with scientific evidence.
Also, it is important to note that ever since we obtained the key to the human genome we have unraveled some of the deepest mysteries and also found out a thing or two about our ancestors. So if the Evangelicals ask “Where we come from?” We can now, with a certain degree of certainty answer: “We come from a mixture of Neanderthals, Denisovans and early Humans.”
So, when these religious fanatics, trying to uphold the Creationist theory that the world is 6,000 years old we can, with confidence present them with the evidence that a new paper, by Prof Zilhao and colleagues from the University of Bristol, revealed new dating evidence for the Late Aurignacian of Portugal, an archaeological culture associated with modern humans, which firmly constrains the age of the last Neanderthals of southern and western Iberia to some 37,000 years ago.
SO, YOU FUNDAMENTALIST-EVANGELICAL EVIL DOERS…EAT YOUR CROW AND KISS OUR SCIENTIFIC BEHINDS.
Tags: Humans, Denisovans, Neanderthals, sex, Papua New Guinea, science, genetics, DNA, Recommended (all tags) :: Previous Tag Versions
SOURCE: http://www.dailykos.com/story/2010/12/22/931027/-New-Evidence-of-Previously-Unknown-Human-Ancestor-
