DNA testing offers window into family ancestry

FRESNO, Calif. (KFSN) -- DNA testing is most often associated with health issues and criminal investigations but there is a new trend in "genealogical" DNA testing. A simple swap of your cheek can trace your ancestry back hundreds or even thousands of years.

Jennings has never met his father and he's always been a bit curious.

"My mom is white, white and I'm a little darker, so I'm like where does this come from," he said.

A friend sent him a link to a viral video from travel website Momondo and Ancestry.com. It showed several people taking a DNA test and having an emotional reaction weeks later upon learning where they came from. Jeremy immediately ordered a test and began putting together the pieces of his own ancestry puzzle.

"Growing up people asked, 'Are you Italian?' I said, 'No, I'm German cause that is what my mom is,' he said. "And then I found out Italian. It kind of made more sense."

So, what's the science behind these mail-order DNA kits? Action News visited the Ancestry.com offices in San Francisco to find out.

Scientists look for common strands in your DNA and the DNA of people who are native to 26 regions around the world. Those similarities determine your ethnicity and where your ancestors once lived.

"Because we get half our DNA from our mom and half from our dad and it's randomized," Ancestry.com spokesperson, Brad Argent explained. "That's why brothers and sisters look so different because they are getting different bits of DNA."

They're even able to determine possible relatives, people with whom you share identical segments of DNA. But just how accurate are these tests?

Action News reporter Graciela Moreno decided to do the test herself and compare the results. She used two of the more popular kits, one from Family Tree DNA requires you to scrape the inside of both cheeks. And another one from Ancestry DNA requires you to spit quite a bit into a vile and send it in for testing."

Both tests were under $100 and the results were pretty eye-opening. According to Ancestry DNA, Graciela is 43 percent Native American, a region that encompasses both continents. She's also 40 percent European, mostly from the Iberian peninsula, which is Spain and Portugal. The results showed some Italian and Greek, a bit British, Asian and African DNA - 13 ethnicities in all.

Argent said my results are not surprising.

"You look at your results, you look at a typical Americans results, Canadians, Australian," he said. "Any country that was built on immigration and there are a lot of them will have a level of diversity flowing through them that they probably don't realize."

The results from Family Tree DNA were similar in the regions but not the percentages. The second test reported more European than Native American, 56 percent and 28 percent, respectively.

Argent explains the percentages are estimates and are relative to the reference panel each company uses.

"You can have a range between 20 and 45 percent and we may say our best guess is 35 percent," he said. "But 20 percent is a viable result as is 45. It's just our best understanding of the maps that we apply to this."

Both companies let you control how much of your DNA results you want to share and with whom. Fresno State professor Joseph Ross warns before you make any information public, you should consider the risks.

"What if your DNA was released to the public and your insurance got a hold or your genome sequence and determined that you had a predisposition to Alzheimer's disease, for example," Ross said. "That is the main reason to; A, Consider whether to have a genetic test done and; B, to share those data with others."

For Jeremy, the discoveries he's made are simply too exciting not to share.

"I literally used to say, 'I'm German and Norwegian,'" he said laughing. "Now I have to get this thing out - 28 percent this, 16 percent this - it actually opens a better conversation. I did this DNA test and I'm all of these things."