Ancient DNA could help California tribe get federal recognition

When Spanish priests arrived in what is now California almost 250 years ago, they established a string of missions stretching from San Diego to the hills north of San Francisco—all built by forced Indigenous labor. Tens of thousands of Native Americans died from disease, malnourishment, and maltreatment during the mission period, which lasted until the 1830s.

By then, California’s Indigenous population had been devastated—including the Ohlone, or Costanoan, people, whose lands once included much of the San Francisco Bay Area. More than 8000 Ohlone perished between 1776 and 1833; from a precolonization population of approximately 30,000, there were fewer than 100 Ohlone left by the 1920s.

In the century that followed, the tribe was written off as vanished. In 1925, University of California, Berkeley, anthropologist Alfred Kroeber wrote that the Ohlone were “extinct for all practical purposes.”

But the Ohlone survived. Today, the tribe has about 500 members. Since 1989, they have been fighting for federal recognition, using genealogy to trace their family histories back to the Spanish mission period and legal documentation to show a long history of tribal presence in the Bay Area.

Now, they’re getting help from genetics. In a new study, researchers have used ancient DNA from two archaeological excavations to identify the Ohlone’s genetic signature and link ancient individuals, some buried nearly 2000 years ago, to their modern-day descendants. “This is fascinating work,” University of Kansas, Lawrence, paleogeneticist Jennifer Raff, who studies the early peopling of the Americas, wrote in an email. “If other tribes are interested in using genetics to investigate histories, they may be encouraged by the fact that some researchers are doing this work in a careful way.”

In 2016, archaeologists working as part of a construction project identified two Indigenous village sites near Fremont, California. Radiocarbon dating showed one site was occupied between 490 B.C.E. and 1775 C.E. and the other between 1345 and 1850 C.E., the latter overlapping with the Spanish colonial era in the region.

Based on the sites’ locations, California authorities recognized the Muwekma Ohlone, a modern group claiming descent from the Ohlone who once lived in the area, as the most likely descendant community. During the excavations, it was members of the tribe who handled most of the human remains.

University of Illinois, Urbana-Champaign, geneticist Ripan Malhi recovered DNA from 12 individuals who had died between 100 C.E. and 1805 C.E. People buried at the two sites shared distinctive genes, suggesting related people inhabited the region for about 2500 years, more in keeping with Ohlone versions of their own history.

Malhi and his colleagues—including members of the Muwekma Ohlone, who also contributed genealogical and oral histories to the study—took eight DNA samples from living tribe members. Because Indigenous Californians have mixed with European, Mexican, and other native populations over the past 200 years, the team set aside DNA signatures more typical of Europeans, then compared the remaining distinctive DNA components. Those components matched those of known Indigenous groups and were more genetically similar to the ancient people from the Fremont sites than to ancient individuals from Southern California and Nevada, the team reports today in the Proceedings of the National Academy of Sciences.

The findings also contradicted older ideas, based on linguistic reconstructions, that the Ohlone first arrived in the Bay Area from the north around 1500 C.E. “Ancestors in the Bay Area were generally closer to ancient individuals from Southern California,” showing the Ohlone were around 1000 years earlier than this linguistic idea, and came from the south, rather than the north, Malhi says. “If there was a movement [from north to south], it was more one of language than people.”

The DNA backs up the Ohlone’s genealogical research, lending their cause legitimacy, says co-author Alan Leventhal, the Muwekma Ohlone’s tribal historian and an anthropologist at San José State University. The tribe hopes the study and others to come will bolster its credibility as it works with politicians to pass laws recognizing it as a tribe at the federal level, giving it legal sovereignty and access to federal programs designed to support tribes.

“By creating these collaborations and having them published with Muwekma co-authors,” Leventhal says, “it’s not just hearsay or self-identification, it’s meaningful science.”

source: sciencemag.org