Field Notes: The Polar Field Services Newsletter

Retracing Alaskan Genealogical Lineage through DNA studies

By Marcy Davis

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An overview of the Nuvuk site and archaeological excavations at Pt. Barrow, Alaska. Photo: Dennis O'Rourke

Researchers believe that humans probably arrived in the North American Arctic toward the end of or following the last Ice Age, about 12,000 years ago, via northern land bridges now covered by shallow seas (the Bering Sea is one example). These nomadic peoples likely followed large herds of caribou, muskox, bison, and mammoth.

Anthropological geneticist Dennis O’Rourke (University of Utah) is fascinated not only by how successfully people acclimatized to life in harsh high-latitude climates, but also how they spread out and settled in the Arctic. In an attempt to get at the details, O’Rourke and geneticist Geoff Hayes (Northwestern University) are giving new meaning to the age-old question “where do we come from,” at least for Iñupiat people of Barrow. O’Rourke and Hayes’ three-year project aims to determine ancestry and lineage in Alaska’s northwest Arctic and North Slope and in the circum-Arctic region.

Deoxyribonucleic acid (DNA) contains genetic information and instructions for cell and protein construction. We each obtain certain DNA components from our mothers and others from our fathers. O’Rourke and Hayes hope to track settlement patterns throughout the Arctic by comparing certain parts of the DNA contributed from mothers and certain parts from fathers in ancient and contemporary populations.

Collecting DNA from Barrow residents is relatively easy. Volunteers rinse with a special mouthwash and spit into a test tube. Their DNA can easily be teased out of their saliva back in Hayes’ lab. Obtaining DNA samples from residents of nearby Nuvuk, however, is a little more involved.

Located at the very end of Point Barrow, Nuvuk is an ancient village site. Archaeologists believe Nuvuk was occupied by the Thule culture, the Iñupiat ancestors, for more than 1000 years until the 1930’s, when it was abandoned. As a result, the only current residents of Nuvuk are found in the cemetery—an old burial ground that is slowly being washed away as the coastline gives way to shifting point sands and beach erosion. An effort has been ongoing for about 10 years to document, stabilize, rescue and relocate the burial sites; this effort also has allowed scientists to study the artifacts uncovered at the sites for information about the ancient people.

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Justin Tackney, PhD student at the University of Utah, works at a sterile workstation on ancient DNA extractions from human remains. The sterile nature of the lab, the workstation, and the 'clean garb' Justin wears, prevents contamination of the ancient samples with modern DNA.

The Barrow community supports and is actively involved in the Nuvuk cemetery effort. “The local community felt this was the right thing to do and gave us permission to do the Nuvuk studies,” O’Rourke explains. “It’s wonderful that they are so helpful and interested in using these approaches to learning and understanding about where their ancestors came from.”

Anne Jensen, an archaeologist and UIC Science Director in Barrow, is working to locate, exhume, and reinter those buried at Nuvuk. O’Rourke and his students cooperate with Jensen, who also involves local high schoolers in the research, as part of a larger collaboration that hopes to trace the heritage of the Nuvuk people.

DNA degrades over time, but Barrow’s cold climate helps preserve DNA in the Thule buried at Nuvuk whose remains can be more than 1000 years old. Ancient DNA samples are easily contaminated, however, so O’Rourke’s team works closely with Jensen to collect very small samples, no larger than a small rib. As soon as specimens are unearthed, researchers cover and then place them in a sterile container.

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Justin Tackney prepares to collect samples for ancient DNA analysis from Nuvuk, Pt. Barrow, AK. Photo: Dennis O'Rourke

The samples are stored in a freezer at Barrow until they are flown back to a clean lab in Salt Lake City. There, scientists chemically treat the samples to release specific DNA sequences. By comparing sequences obtained from the Nuvuk population to other ancient populations along the North Slope, southern Alaska, eastern Canada, and Greenland–and to contemporary populations at Barrow and around the Arctic–O’Rourke and Hayes can determine not only who’s related to whom and how closely related people are in time and space, but how people moved around and settled in the Arctic region.