Why you're no longer 5% Portuguese: Ancestry explains DNA update

Ancestry, the popular genealogy website, is offering more explanation about why some customers who took DNA tests to learn about their ethnic backgrounds have seen some of their more surprising results disappear.

Barry Starr, the company's director of scientific communications, said Ancestry now has more "reference" samples from people who have long family histories in specific regions, and the algorithm it uses to compare results has also changed.

"As the science progresses, we're going to get more precise results, which means some of those what we called before low-confidence regions go away," he said in an interview from San Francisco.

When Colin Duggan, originally from Antigonish, N.S., took his test two years ago, it showed he was mostly Scottish and Irish, but noted five per cent from the Iberian Peninsula, which includes Portugal and Spain.

That blip disappeared from his results following an update from Ancestry Sept. 12. It turns out he's even more Irish and Scottish.

"For me, that's a pretty significant change," he said. "It's the little [results] that kind of give you that link to new parts of your identity."

Starr said the updated algorithm "makes us better able to more precisely put you into a certain ethnicity." This could explain why some people with European ancestry may have seen their ethnicities recalibrated.

"Europeans are actually pretty similar genetically, their history is migrations and taking over each other and all kinds of things ... they're not easy to tell apart," Starr said.

"And what's one of the great things in this new update is we're much better able to tell Europeans from one another and more precisely give them their European region."

More samples

Each DNA kit comes with a tube and directions to create an online profile with the site. Customers mail a saliva-filled test tube to the company's lab in Ireland. The results of the test are later posted to the profile.

Ancestry had previously termed some regions "low confidence" and always said a person's test results could change over time as methodology improves.

Starr said ethnicity estimates are compiled by comparing a customer's DNA to the DNA of people who have a long family history in a certain region of the world.

In the update this month, there was more DNA — 16,000 samples, up from 3,000 samples — to compare customer results.

While the company doesn't know how many people saw dramatic changes to their results, Starr said most of the feedback on the update so far has been positive.

"The vast majority were satisfied with the changes and many of them expressed that the changes better reflect the family history that they know," Starr said.

Duggan said he finds his new results more interesting.

"In general, to me, it seems like the product is more specific to what I provided them," he said.

Fascinated with genealogy

Reality television star Stephanie Saint Remy, who once appeared in the U.K. version of Married at First Sight, which matches people based on scientific methods like DNA, took the Ancestry DNA test more than two years ago.

Even though she hasn't seen the updated results, she isn't worried about what they'll show and plans to visit each country mentioned.

"I'm so fascinated with genealogy and DNA and general scientific advances," she said. "No matter what they say, even if it's a case where, oh, I'm not this culture, I'm that — I won't find it a disappointment because it's actually an advance in technology.

"It's not a case of they were wrong the first time, it's just a case that the science has kind of caught up."

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