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.”