FOX59 Finds Out: How accurate are DNA ancestry kits?

INDIANAPOLIS, Ind. - DNA kits have become very popular in recent years. All it takes is a swab of your mouth and companies promise to reveal where you come from. But how accurate are these tests?

FOX59 put two of the biggest genealogy companies to the test.

We asked four FOX59 employees who previously took a DNA test on their own, to do it again. We wanted to see how their new results matched up with their original results.

First up, FOX59 meteorologist Jim O'Brien. Jim's new ancestry result came back pretty close the original. He is mostly Irish.

"That made me feel a little bit better knowing after taking it twice that I'm definitely Irish," said O'Brien.

Next, we tested Neal Moore. His second ancestry results confirmed the first. He is definitely English. Although, this time, he appeared to be even more British.

"Being an anglophile, I'm a little bit more British, so eh, that's cool," Moore said.

The other, however, came back with some questions.

Brandi Ostojic's late father was from Austria. But her original 23andMe results didn't show any Austrian in her. Her new results do.

"It was just kind of strange to see that it was different each time," she admitted.

Jordan Morton's results were the most confusing. Originally, 23andMe said she was mostly French and German. Her second test revealed she's mostly British and Irish.

"I had two tests that have two completely different things!"

We took our results to 23andMe and Ancestry DNA.

Ancestry DNA has not gotten back to us yet, but a 23andMe spokesman explained the differences in results this way:

"The main reason for the difference is that in both cases these customers connected with a parent on one account but not the other. By connecting with a parent it allowed for phasing of the data that in turn generates a more accurate and fine tuned Ancestry Composition."

"I would suspect that's the biggest reason for differences," concurred Gabriel Zentner, an Assistant Professor of Biology at IU.

Inside a lab at the Indiana University Bloomington campus, Zentner and his team are working with DNA. He explains how the blueprint for life contains SNPS, or differences in the genome that make people different.

Zentner said DNA companies are comparing some of your SNPS to others from around the world.

"How many SNPS do you have? And do these SNPS match better with folks from Africa or Europe?" he explained.

The more data they have, the more accurate your results.

"If they did it a year apart and 5,000 more customers from the same part of the world submitted samples, they would've been able to further refine their methods and database and perhaps give you a more accurate read on your SNP profile," he said. "The science, I think, is good in each case, but the fact is, it's imprecise."

In Jordan's case, 23andMe was right. Her results changed when she linked them to her parents. But that made her wonder, just how accurate are these tests on their own?

"I don't know if you can 100% trust just your result by itself," she said. "I think you have to have your parents or sibling or some other relation to get the more accurate result."

Zentner reminds folks to take these results with a grain of salt and not to change your identity just because a company tells you something different.

"If what you're seeing with your DNA test doesn't jive with the known family history, I would trust the family history over the genetic testing."