‘Pocahontas’: Elizabeth Warren’s DNA, what Trump said, and the limits of DNA tests

The test was done after Warren’s claim to Native American ancestry had been derided by critics including President Donald Trump  who refers to her in campaign speeches as “Pocahontas.”

According to Warren’s test results her DNA shows a distant Native American ancestor dating back between six and 10 generations.

Warren submitted her DNA material to Carlos D. Bustamante, a Stanford University professor who won a MacArthur Scholarship for his work on tracking population migration via DNA analysis.

Warren provided the Boston Globe with the results of Bustamante’s test in which he determined her DNA sample “strongly” supports her claim of Native American ancestry.

“We find strong evidence that a DNA sample of primarily European descent also contains Native American ancestry from an ancestor in the sample’s pedigree 6-10 generations ago. We find little or no evidence of African ancestry in this sample,” the report read.

The report from the DNA test was distributed by Warren's staff to reporters Monday morning along with a video on her childhood, according to the Washington Post.

Warren has said that she was told by her mother that her great-great-great-grandmother, OC Sarah Smith, was at least partially Native American.

If the results are correct, it would mean Warren would be at least 1/64th Native American. If the Native American ancestor in Warren's family is from 10 generations back, that would mean she is 1/1,024th Native American.

Warren has faced criticism that she used a claim of Native American ancestry to advance her career. During the time Warren was a law professor at Harvard, she changed her ethnicity on personnel forms from “white” to “Native American.”

Warren told the Globe that she began to identify herself as a Native American in the late 1980s, when she felt her family heritage was as risk of being forgotten as the matriarchs of her family were dying.

The Guardian reported in September that Harvard officials denied the reason they hired Warren after she changed her ethnic status to "Native American" was to increase numbers of non-white faculty members at the college.

Warren’s claims about Native American heritage came to light during her 2012 run for the Senate. When she began to speak out against Trump as he campaigned for president, Trump began to attack her claims and dub her “Pocahontas.” At one time, Trump had promised to donate $1 million to the charity of her choice if Warren would take a DNA test and release its findings.

In a series of tweets on Monday, Warren called in the bet, telling Trump to pony-up the $1 million to charity.

“NIWRC is a nonprofit working to protect Native women from violence,” Warren tweeted. “More than half of all Native women have experienced sexual violence, and the majority of violent crimes against Native Americans are perpetrated by non-Natives. Send them your $1M check.”

Warren, 69, is seeking re-election in November and will face the winner of a Republican primary on Tuesday.

The DNA test Warren took looks at a person’s genetic makeup and is able to match certain of their DNA markers to people in other groups with similar DNA markers. This process helps researchers determine where a person’s ancestors may be from based on DNA similarities.

Here’s how DNA testing works:

You may be familiar with the companies that offer DNA testing to help you get a better look at your ancestry.

Customers receive a packet, register it and mail in samples of their spit. After about two months, they receive reports on where their ancestors may have been from.

In Warren’s case, the majority of her DNA traced back to European groups. Some of her DNA, according to the results, has the same markers as people who are descended from Native Americans, indicating that at least some of her ancestors were Native American.

How is your DNA used to find out where you come from?

The saliva that is sent into DNA testing groups is separated and digitized into a series of letters – A, C, G and T -- that researchers then process. The letters correspond with four nucleobases – or substances that join together to form DNA. 

An algorithm, or a set of rules a computer uses when it is trying to achieve a set goal, is then used to decode the series of letters and spot patterns among them.

Researchers then use those patterns to compare the DNA sample to a large library of other DNA samples. When your DNA sample matches a group in one of those libraries, it means your ancestors and the ancestors of those in that group likely share a common heritage.

For instance, if your DNA sample is collected, separated, analyzed then matched with a group of people whose DNA has been found to come from England, then it is likely that some of your ancestors came from England as well.

How do researchers know which country or region the DNA suggests people come from?

Researchers determine where DNA comes from in a couple of ways.

According to a story from Live Science, ancestry groups are made from a mix of self-reports (where people have been able to trace their ancestry back generations through family records or genealogy tools), and independent research.

Researchers have found that people who have ancestors from the same region share certain DNA matches.

How accurate are the tests?

The tests are as accurate as the algorithm used to match them to other samples and the libraries those samples are in.