Elizabeth Warren Might Be Between 1/64th and 1/1,024th Native American

[Warren's great-great-great-grandmother, O.C. Sarah Smith] was born in the late 1700s. She identified as white in historical documents, though at the time Indians faced discrimination, and Smith would have had strong incentives to call herself white if possible.

The inherent imprecision of the six-page DNA analysis could provide fodder for Warren’s critics. If O.C. Sarah Smith were fully Native American, that would make Warren up to 1/32nd native. But the generational range based on the ancestor that the report identified suggests she’s between 1/64th and 1/1,024th Native American. The report notes there could be missed ancestors.

[...]Warren provided a sample of her DNA to a private lab in Georgia in August, according to one of the senator’s aides. The data from that test was sent to [Stanford University professor Carlos D. Bustamante] and his team for analysis. Warren received the report last week.

Warren didn’t use a commercial service, but Bustamante is on the scientific advisory board for Ancestry, which provides commercial DNA tests. He’s also consulted on a project for 23andMe, another major DNA testing company.

Warren said she was committed to releasing the report regardless of the results. However, Warren’s aides would not say whether she or any of her three siblings had previously done a commercial DNA test that would have provided them with some assurance about Bustamante’s analysis.

There were five parts of Warren’s DNA that signaled she had a Native American ancestor, according to the report. The largest piece of Native American DNA was found on her 10th chromosome, according to the report. Each human has 23 pairs of chromosomes.

“It really stood out,” said Bustamante in an interview. “We found five segments, and that long segment was pretty significant. It tells us about one ancestor, and we can’t rule out more ancestors.”

He added: “We are confident it is not an error.”

Detecting DNA for Native Americans is particularly tricky because there is an absence of Native American DNA available for comparison. This is in part because Native American leaders have asked tribal members not to participate in genetic databases.

“The tribes have felt they have been exploited,” explained Lawrence Brody, a senior investigator with the Medical Genomics and Metabolic Genetics Branch at the National Institutes of Health. “The amount of genetic data that is available from Native Americans is sparse.”

To make up for the dearth of Native American DNA, Bustamante used samples from Mexico, Peru, and Colombia to stand in for Native American. That’s because scientists believe that the groups Americans refer to as Native American came to this land via the Bering Strait about 12,000 years ago and settled in what’s now America but also migrated further south. His report explained that the use of reference populations whose genetic material has been fully sequenced was designed “for maximal accuracy.”

Bustamante said he can tease out the markers that these South Americans would have in common with Native Americans on the North American continent.

Bustamante also compared Warren’s DNA to white populations in Utah and Great Britain to determine if the amounts of Native American markers in Warren’s sample were significant or just background noise.

Warren has 12 times more Native American blood than a white person from Great Britain and 10 times more than a white person from Utah, the report found.