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Genomic sequencing confirms Indigenous tribe has deep roots in the San Francisco region

The Muwekma Ohlone Tribe has inhabited the San Francisco Bay Area for at least 2,000 years, according to new genomic evidence, disproving the notion that they arrived more recently.

(CN) — Researchers found that modern-day members of the Muwekma Ohlone Tribe located in and around the San Francisco Bay Area can trace their roots in the region back more than 2,000 years.

By comparing genomic data from eight present-day tribe members with DNA extracted from 12 individuals who lived nearby between several hundred and 2,000 years ago, researchers confirmed the tribe has ancient ties to the region. Much of the past work on the topic has focused on broad-scale migration patterns across North America, and until now little attention was paid to local population dynamics.

The research team published their findings Monday in a new study in the journal PNAS, which refutes an earlier notion that the tribe migrated to the Bay Area sometime between 500-1000 AD. Past archeological and linguistic research had suggested that the Ohlone arrived in the area during that period, but the authors’ genomic analysis demonstrates that isn’t the case.

“We analyzed a large number of ancestral remains for DNA preservation and focused on those with the best DNA preservation for this study,” said Dr. Ripan Malhi, a professor of anthropology at the University of Illinois Urbana-Champaign, in a related statement. “We also worked with the Ohlone to sample saliva from present-day community members so we could compare the DNA from both groups.”

The authors sought to take a more inclusive approach in their work and worked closely with tribe members to design and carry out the study. The Ohlone Tribal Council approved the design of the study and met regularly with the authors to review their progress.

By utilizing recent advances in genomic sequencing technology, researchers were able to compare nuclear DNA extracted from Indigenous individuals living in California with those residing elsewhere across North America to look for similarities.

To conduct their analysis, the authors took saliva samples from modern-day members of the Muwekma Ohlone Tribe and compared them with DNA retrieved from the Tribe’s ancestral remains located in two Bay Area villages. One of the villages persisted from around 490 BC to 1775 AD, and the other from 1345 to 1839 AD, which were both excavated at the request of the Muwekma Ohlone Tribal Council prior to subsequent infrastructure construction on the sites. The ancestral remains were primarily excavated by tribal members themselves, who also participated in other aspects of the fieldwork.

“Part of what we wanted to do is not just rely on the genomics but to have a more holistic approach of having community knowledge or traditional knowledge and genealogical information – along with all the archaeological documentation – to tell the story,” Malhi said.

At the time of European contact, California was home to numerous distinct Indigenous groups speaking more than 78 mutually unintelligible languages from six major linguistic families, hosting one of the most diverse Native American populations in North America. By studying Spanish mission baptismal recruitment records, researchers revealed that more than 15,000 Native Americans from five different language groups lived in sedentary villages within 45 miles of the bay at the time of European contact.

“Because of the disruption of the mission period and because of multiple ancient migrations in California, we did not know what to expect for the level of continuity between the ancient sites and the modern population,” said Noah Rosenberg, co-author of the study and professor of population genetics at Stanford University, in an email. “It was a bit of a surprise to see that a genetic signal of connection remains.”

Further investigation led the authors to discover that Native Americans had lived in sedentary villages sprinkled throughout the area for more than 5,000 years before Europeans arrived in the State. The authors were able to identify genetic links between ancient and modern Ohlone populations despite the massive upheaval that occurred in Indigenous communities during the Spanish occupation and the region’s subsequent transfer of control from Mexico to the United States.

Mission records also document the ongoing intermixture with nearby non-Ohlone tribes that began when these groups were brought to the same missions by settlers, making the task of determining their individual origins that much more difficult.

“We were able to find one ancestral component from their genomic analysis that was shared with ancient people from the Bay Area,” Rosenberg said. “The Ohlone living today who participated in the study may not be direct descendants of the ancient people whose genomes we sequenced, but the analysis suggests they descended from the broader population to which those ancient people belonged.”

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