PULLMAN, Wash.--For more than a decade, Washington State University molecular anthropologist Brian Kemp has teased out the ancient DNA of goose and salmon bones from Alaska, human remains from North and South America, and human coprolites--ancient poop--from Oregon and the American Southwest.
His aim: use genetics as yet another archaeological record offering clues to the identities of ancient people and how they lived and moved across the landscape.
As head of the team studying the DNA of Naia, an adolescent girl who fell into a Yucatan sinkhole some 12,000 years ago, he has now helped illuminate the origins of the first people to inhabit the Americas and their possible connection to native people today.
"It's incredible to make such a discovery," said Kemp, an associate professor in WSU's Department of Anthropology. "It is an honor to be able to use the skills I have acquired to address classic questions about the entrance of humans into the Americas."
Writing in the current issue of the journal Science, a 16-person team reports that Naia had a skull shape different from modern Native Americans. Such skull shapes have led researchers in the past to hypothesize that such people were from a separate population that came from as far away as Polynesia. But Kemp's genetic analysis found a link between Naia and modern Native Americans, supporting a theory that they are of a population that "evolved in place" in the Americas.
Kemp undertook his analysis at the request of Jim Chatters, the study's lead author and owner of Applied Paleoscience, an archaeological and paleontological consulting firm in Bothell, Wash. Chatters is perhaps best known for leading the work on Kennewick Man, the prehistoric man discovered near Washington's Tri-Cities in 1996. Working out of College and Eastlick halls on WSU's Pullman campus, Kemp analyzed mitochondrial DNA from a third molar that a technical diver pulled from the skeleton some 140 feet below the water's surface.
Chatters said he chose Kemp because he has experience dealing with small amounts of fragmentary DNA. Mitochondrial DNA, found in the energy generating structures in a cell nucleus, helped that cause, as organisms have many more copies of it than chromosomal DNA.
Still, said Kemp, "There is very little DNA preserved in a skeleton of such great antiquity." Using basic molecular biology techniques to amplify the DNA, he made hundreds of billions of copies of the original material.
"Once so many copies are made," he said, "it is pretty straightforward to study the DNA." After the sequences confirmed Naia's maternal lineage as Native American, Kemp asked some of his most trusted colleagues, Deborah Bolnick at the University of Texas-Austin and Ripan Malhi at the University of Illinois Champaign-Urbana, to help verify my results. They did. Kemp and his colleagues are now working on a follow up study to sequence more of Naia's genetic material.
"Naia is one of only a few skeletons found in the Americas that date to between 12,000 and 13,000 years ago, so ultimately we would like to sequence her entire genome," he said. "Current technology permits this, but it will still be challenging."