Story last updated at 12/24/2008 - 10:50 am
Preliminary results from DNA research on ancient human remains discovered in Southeast Alaska did not establish a genetic connection to potential living descendants from the region. However, scientists are not ruling out eventually finding a genetic link between Southeast Natives and the 10,300-year-old man, who was given the name Shuká Kaa (Man Before Us) by Native people in September at his burial.
"It is important to note that the mitochondrial DNA test only addressed direct maternal ancestry," said Washington State University Molecular Anthropologist Dr. Brian Kemp, lead researcher for the project. "It is still possible other DNA markers could connect present-day indigenous Southeastern Alaskans to Shuká Kaa. However, these were not tested for."
The results did not rule out a direct connection between Shuká Kaa and Southeast Natives along the paternal line. However, scientists know significantly more about mitochondrial DNA, which is passed through the mother, than they do about DNA in the Y chromosome, which is passed through the father.
Although Y chromosome variation in some populations, such as among European males, has been fairly well established, little is known about the diversity in the Y chromosome in Native American males. Scientists are years away from being able to deduce relations on the paternal line in Native men with the precision that is available now on the maternal side, Kemp said.
Native people anticipated scientists might not find a link through mitochondrial DNA, said Rosita Worl, president of Sealaska Heritage Institute, which sponsored the research. Before the study, Worl cautioned in a press release that researchers might not identify Shuká Kaa's DNA type in people living today because DNA markers can disappear from small populations very quickly.
"We do know that DNA markers pass out of populations, and they disappear. It may not be transferred to future generations, so we know that was a possibility," she said.
More than 230 Native people participated in the study, making it one of the largest samples ever collected in the Americas, Kemp said. Native people here participated in greater numbers because the Native concept of Haa Shágoon (Tlingit), żżitl' Kuníisii (Haida) and Hlaagigyadm (Tsimshian) unites Native people to their ancestors and to future generations, Worl said. However, the DNA marker found in Shuká Kaa is very rare, so genetic links on the maternal side might have been found if a larger group of people had participated.
"It was a very rare DNA marker, and actually it's only found among 1.5 percent of Native Americans and so it could be our study population was too small," Worl said.
It's also possible Shuká Kaa represented an older population and that the people who were tested came from a later group, said Worl, who wrote a paper on her hypothesis that the Tlingit population derived from two different populations.
The remains were found in a cave on Prince of Wales Island in 1996. Local tribes from Craig and Klawock authorized scientists to study the bones after determining they were not associated with a grave site but scattered in the cave, possibly by scavengers.
It turned out to be one of the more important archaeological sites found in North America in recent years. Scientists dated the bones and found them to be the oldest human remains ever discovered in Alaska and Canada. Kemp and a team of colleagues extracted DNA and found Shuká Kaa was of Native American ancestry and carried a very rare mitochondrial DNA type called D4h3.
Sealaska Heritage Institute sponsored DNA research June 5-7 during Celebration 2008 in hopes of finding living descendants of Shuká Kaa in Southeast Alaska. Kemp and his colleague, Kari B. Schroeder from the University of California, Davis, collected DNA samples from more than 230 Native people in the form of saliva. The preliminary results show none of the participants belong to the haplogroup D and therefore none is related on their direct maternal line to Shuká Kaa.
Scientists will use the results to also study the genetic variation among Alaska Natives and other indigenous populations, to learn about the genetic continuity of populations in Alaska and their relationships to other indigenous populations and to reconstruct population history. The preliminary results are already showing long-distance genetic links among Native people along the coast from Washington to Southeast Alaska.