WASHINGTON (Reuters) – Scientists have sequenced the DNA from four frozen hairs of a Greenlander who died 4,000 years ago in a study they say takes genetic technology into several new realms.
Surprisingly, the long-dead man appears to have originated in Siberia and is unrelated to modern Greenlanders, Morten Rasmussen of the University of Copenhagen and colleagues found.
"This provides evidence for a migration from Siberia into the New World some 5,500 years ago, independent of that giving rise to the modern Native Americans and Inuit," the researchers wrote in Thursday's issue of the journal Nature.
Not only can the findings help transform the study of archeology, but they can help answer questions about the origins of modern populations and disease, they said.
"Such studies have the potential to reconstruct not only our genetic and geographical origins, but also what our ancestors looked like," David Lambert and Leon Huynen of Griffith University in Queensland, Australia, wrote in a commentary.
The DNA gives strong hints about the man, nicknamed Inuk. "Brown eyes, brown skin, he had shovel-form front teeth," Eske Willerslev, who oversaw the study, told a telephone briefing. Such teeth are characteristic of East Asian and.
He had the genes for early hair loss, too. "Because we found quite a lot of hair from this guy, we presume he actually died quite young," Willerslev said.
The man lived among the Saqqaq people, the earliest known culture in southern Greenland that lasted from around 2500 BC until about 800 BC.
Scientists have disagreed on who these people were -- whether they descended from the peoples who crossed the Bering Strait 30,000 to 40,000 years ago to settle the New World or whether they were more recent immigrants.
Willerslev's team pulled DNA from hairs found in a frozen Saqqaq site and sequenced it just as they would a modern person's full genome, looking for characteristic mutations.
"Recent advances inhave initiated an era of personal genomics," the researchers wrote.
"The sequencing project described here is a direct test of the extent to which ancient genomics can contribute knowledge about now-extinct cultures," they added.
The DNA links Inuk to modern-day Arctic residents of Siberia. He had almost none of the mutations seen in Indians living in Central and South America.
"We have an increasingly powerful forensic tool with which to 'reconstruct' extinct humans and the demographics of populations," Lambert and Huynen wrote.
A year ago scientists sequenced the genome of a early humans who went extinct 30,000 years ago -- and other groups have sequenced DNA from dried-out mammoth hair.--
(Editing by Cynthia Oysterman)
Scientists decode ancient man's genes
David Perlman, Chronicle Science Editor
Thursday, February 11, 2010
He died there on an offshore island now called Qeqertasussuk - of what cause no one knows, but he left four tufts of his hair and a few bits of bone frozen into the permafrost, and now those thawed scraps tell a remarkable story through the updated alchemy of the Human Genome Project.
For the first time, a team of 53 international scientists has sequenced the genes of an ancient human - a "Palaeo-Eskimo" - and learned more details about him than anyone might have expected.
The gene analysts also revealed new insights into the hotly debated
migration patterns of Old World people into the New World, the scientists
Inuk's genes reveal he was a fairly young man, robustly built to exist in a frigid climate, with A-positive blood, dark skin, brown eyes, and thick, black hair on a scalp genetically susceptible to baldness. His ear wax was dry - unlike that of most Europeans and Americans, and his genes determined that his front teeth were shovel-shaped, a characteristic of many Asian people today.
He belonged to a culture called the Saqqaq, a Greenland people whose
forebears had apparently migrated to the huge glacier-capped western side of
that island from far northeastern Siberia about 5,500 years ago.
Archaeologists have found that the people of Inuk's culture became extinct many hundreds of years later, leaving only the name Saqqaq to denote a tiny, remote coastal village of 200 Greenlanders.
Inuk's genetic details are being reported today in the journal Nature, and they result from a major project led by two Danish genome specialists with collaborators in America, Britain, France, Australia, China, Russia and Estonia.
Morten Rasmussen and Eske Willerslev, of the Natural History Museum of Denmark and the University of Copenhagen, were the leaders of the project, which used technologies far more advanced than the gene sequencing techniques of the original Human Genome Project in 2003.
From Inuk's hair the scientists sequenced 79 percent of his entire genome 20 times and analyzed 350,000 variations in his DNA base pairs, known as single nucleotide polymorphisms, or SNPS, and pronounced Snips.
The technique was far more detailed than the sequencing of DNA from a Neanderthal man's genome that was reported four years ago by Eddy Rubin of the Department of Energy's Joint Genome Research Institute in Walnut Creek and Svante Paabo of the Max Planck Institute in Germany.
A look into the past
In a phone conversation, Rubin said the sequencing of the ancient human's genome in such detail "gives us a real time machine to look into humanity's past. ... Before long, as the technology advances, we'll be able to learn even more about human differences and similarities in great detail."
In a joint telephone press conference Tuesday, Rasmussen and Willerslev said tiny bits of Inuk's frozen remains were found years ago at a site well known to archaeologists and stored in a plastic bag in the Copenhagen museum before they took on the project.
"We named him Inuk because it means man or human in Greenlandic,"
By comparing Inuk's genes with those of indigenous people in many countries of northern Europe and Asia, the project's scientists determined that his ancestors were Siberia's Chukchi people, Greenland's earliest human settlers, who had migrated there from eastern Siberia by traveling more than 2,000 kilometers - about 1,250 miles - across the Bering Strait.
That migration was remarkable, Willerslev noted, because the Bering Sea was open then, and Inuk's forebears would have reached Greenland either by paddling primitive boats across the open sea, or possibly by slogging on foot across miles of endless ice, Willerslev said.
Scientists have long debated where those early Greenland people came from, and many have held that Greenland's first settlers - the people of the Saqqaq culture - were ancestors of today's Native Americans and the Inuit people of the high Arctic.
But by matching Inuk's genes with modern ones, it is now clear that Inuk was Siberian - neither American nor Inuit, the researchers conclude.