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Sunday, November 28, 2021

DNA study suggests Native Americans descended from single ancestral population

Isaac Kinney is a UC Davis senior Native American studies major and Yurok Tribal member; Hailey Chevelle Ferroni is a sophomore psychology major and of the Pomo people; Jeremy Little Fox Bill is a sophomore English and Native American studies double major and Mono, Waksachi and Tachi California Native.

Their backgrounds are uniquely different yet distinctly similar; Kinney, Ferroni and Bill are all Native Americans.

But the beliefs of their peoples’ unique origins – long established by oral traditions rooted in generations of their respective cultures -have now been confronted by an alternate perspective. A recent DNA study led by UC Davis scientists, among others around the country, strongly suggests that Native Americans descended from a single ancestral population.

To researchers, the findings might provide the key to decades old academic debates over Native American origin and migration. But to Kinney, Ferroni and Bill, the findings are ethnically contentious and culturally superfluous.

The research compared DNA data of Native American, Eurasian, African and Oceanian groups in an effort to better understand the prevalence of a specific genetic variant unique to modern-day Native Americans and Western Beringians, according to Kari Schroeder, Ph.D., a lecturer at UC Davis and the first author on the study.

Previous research identified a specific allele known as the “9-repeat allele” (a genetic variant that does not have biological function) present in 44 native populations from Alaska to Chile, and Greenland to the western side of the Bering Strait, but absent in all 54 Eurasian, African and Oceanian groups sampled.

The variant is specifically located at a genomic region known as the microsatellite D9S1120. A microsatellite is genetic coding where short sequences of DNA are repeated in coupled arrangements.

“Earlier studies of this allele suggested that Native Americans descend from a single ancestral group,” Schroeder said.

These studies, however, could not rule out two possible alternative explanations – that mutations resulting in the 9-repeat allele occurred in more than one person and that natural selection has affected the geographic distribution of the 9-repeat allele.

“We analyzed 500,000 base pairs around the microsatellite to better understand the history of the allele among the various sampled populations,” Schroeder said. “We did not find evidence of natural selection or multiple mutations and so concluded that the geographic distribution of the 9-repeat allele strongly supports the hypothesis of a single ancestral population.”

The single ancestral population hypothesis theorizes that all contemporary Native Americans derive from a single source, likely somewhere in Northeast Asia, Alaska or the region in between now covered with water, said Ripan Malhi, an assistant professor with the anthropology department at the University of Illinois Urbana-Champaign and co-author of the study, in an e-mail interview.

Approximately 20,000 years ago during the Last Glacial Maximum, Northeast Asia was connected to Alaska, a region called Beringia, where ancestors of modern Native Americans were isolated, he said. But around 17,000 years ago when the glacial ice melted, the population was able to move into the Americas and bring with it unique genetic variations almost exclusive to Native Americans such as the 9-repeat allele of D9S1120.

Although many in the scientific community might acknowledge the research in support of this hypothesis, others in the Native American community are hesitant.

There are too few American Native Nations that possess sufficient numbers of unmixed “fullbloods,” to provide reliable data, said Professor Emeritus Jack D. Forbes, with the UC Davis Native American Studies department, in an e-mail interview.

“Ancient American history should depend upon the use of many different methodologies,” he said. “Linguistics and other disciplines might well shed some light upon this data. We must regard all studies as preliminary which are developed using only one type of evidence.”

Native American students Isaac Kinney, Hailey Chevelle Ferroni and Jeremy Little Fox Bill are more skeptical.

“Questions don’t need to be answered when solutions are already given,” Kinney said. “The theory takes indigenous knowledge and traditions and completely disregards them.”

“Scientific thought often has little respect for spirituality,” Ferroni said. “It makes me think about who’s doing the research and the kinds of answers they want.”

“It’s just another study that isn’t going to change what I think,” Bill said.

Accordingly, the researchers believe that this is only one outlook on history among many, but very promising nevertheless.

“With genetic data, we can only offer a biological perspective on human prehistory,” Schroeder said. “Some people may place greater value on other perspectives, such as those based on faith.”

Professor David Smith, UC Davis anthropology department and co-author of the study, believes that a mixed reaction is inescapable and speaks not to the validity and utility in the study but to the controversy that inevitably arises from new information.

“This work provides great academic perspective that will hopefully lead to cross-discipline agreement among linguists, archeologists and anthropologists for reconciliation in population theory,” Smith said. “But to groups who still hold on to traditions to explain origins, unfortunately, science will provide contentious information in those circles. It’s just a progression seen in all facets of life where old knowledge and new knowledge must try to reconcile.”

 

DAVID LAVINE can be reached at campus@theaggie.org.

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