What Does Elizabeth Warren's DNA Test Prove?

The results - which identified Native American DNA from six to 10 generations ago - were immediately misinterpreted. It started with a Boston Globe report, which initially indicated the test showed she was at best 1/32nd Native American and possibly just 1/512th Native American. After confessing twice to a math error, the Globe corrected the numbers to 1/64th and 1/1,024th Native American. That would translate to between 98.44 per cent and 99.9 per cent not Native American.

The Republican National Committee then issued a news release directing reporters to a 2014 New York Times report that said "European-Americans had genomes that were on average 98.6 per cent European, 0.19 per cent African and 0.18 Native American." So it sounded like Ms Warren had less Native American DNA than the average European American.



The Fact Checker even issued a tweet along these lines (at a moment when the Globe still indicated the range was between 1/32nd and 1/1,024th): "So Elizabeth Warren could be 3.1 per cent Native American - or as little as 0.01 per cent Native American."

But it turns out reporters and politicians are not very good at understanding genetics. So we will set the record straight, after reviewing the results in detail and consulting with genetics experts.

Ms Warren's DNA was sequenced and analysed by a group led by Carlos Bustamante, a well-regarded Stanford University geneticist. Researchers studied a fraction - far less than 1/1,000th - of Ms Warren's DNA, and then compared it to the DNA of 148 people from Finland, Italy, Spain, China, Nigeria and North and South America. Additional comparison was done on 185 individuals from Utah and Great Britain.



As one might expect, the vast majority - 95 per cent - of Ms Warren's DNA indicated European ancestors. But five genetic segments were identified, with 99 per cent confidence, as being associated with Native American ancestry. The largest segment identified was on Chromosome 10.

"While the vast majority of the individual's ancestry is European, the results strongly support the existence of an unadmixed Native American ancestor in the individual's pedigree, likely in the range of 6-10 generations ago," the report said.

Here is where the reporting went off course. The report said Ms Warren had 10 times more Native American ancestry than the reference set from Utah and 12 times more than the set from Britain.