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LEHI – Twitter, Facebook and other social networking networks appeared a few months ago as a result of changes made to the DNA analysis by Ancestry.com, which have changed , sometimes drastically, the ethnicity profile that the company has provided to millions of customers.
While some clients pointed out that the changes were close to what they knew of their wealth in other ways, such as historical records, many online commentators were outraged by the discounted results.
Earlier this month, Alexis Wore, a Twitter user, published in his Ancestry.com update results indicating an initial profile of ethnicity that placed it at 52% of the Senegalese population, at 26% in Nigeria and less than 1% in Mali. After the analysis of Ancestry.com has changed, these numbers have increased to 48% in Mali, 14% in Senegal and about 3% in Nigeria. His response was representative of many customer comments about changes to their own reports.
"How can my results change so much," wrote Wore. "Were the first ones inaccurate?"
The Director of Scientific Communications at Ancestry.com, Barry Starr, explained that the changes observed by customers resulted from two important changes brought by the company to the way it analyzes the DNA extracted from saliva samples. submitted.
According to Starr, Ancestry.com has significantly expanded its panel of DNA test references, a set of genetic samples that have clear, genetically-related links to specific geographic regions. While the company used a reference panel of approximately 3,500 samples, it then expanded to approximately 18,000 samples. In addition, Starr pointed out that the company was now looking for matches in DNA strings, as opposed to its previous technique of identifying single-marker matches. According to Starr, both of these changes are improvements that reflect the progress being made in the broader area of genetic research.
"It's really a cutting-edge science," Starr said. "What we're looking at is hundreds of thousands of genomes all over their DNA, and with our previous method we're looking at these markers in isolation, and with the new approach we're looking at whole segments, or chains, that are getting closer. better than what happens when the DNA is transmitted. "
Starr said that Ancestry.com's evaluation procedures upgrades have allowed the company to differentiate some new geographic locations more specifically than the old technique. For example, while some genetic markers were simply reported as evidence of a client's "Scandinavian" heritage, the company now specifies the Swedish and Norwegian origins.
Mr. Starr said that the huge amount of DNA samples from Ancestry, representing more than 10 million individuals, had helped the company improve its approach. and expand its reference panel.
"One of the great advantages of Ancestry is that many of our clients rely on family tree research, which means that we can validate, from the point of view of documents, the information on the origin, "Starr said. "By improving our reference panel, we get a better understanding of what markers are common and which ones can differ in population."
Aaron Quinlan, a professor at the University of Utah in Human Genetics, said that it was important to distinguish between a person's genealogical records and genetic evidence when they were in charge. it was to track an ethnic group via DNA.
"Our sense of genealogy is a story that can be supported by historical and family records," said Quinlan. "And, while many people think that we can find the DNA of many generations, we really can not get useful information about seven generations."
Quinlan explained that the genetic makeup of each individual represents about half of a contribution from each parent. A rank in the family tree, and each of these parents receives half of their genes from a parent, and so on. Attempting to gather an image of our ethnic histories, based on this monitoring, becomes very unclear.
"The way I like to think about it is like a quilt," Quinlan said. "The more we go back in time, the smaller the genetic information patch remains – companies like Ancestry and others are trying to compare patchwork to patchwork."
Quinlan, who teaches genetics and studies rare genetic diseases, said the changes that Ancestry had implemented to look for string matches instead of individual benchmarks correspond to changes in genetic research. He noted that the technique "is more informative because they are usually inherited in groups".
Julie Thurgood-Johnson, a student at the University of Utah and a part-time genealogist, said she noted the changes in her own ethnic profile when Ancestry.com updated her analyzes and noted that The revisions were more in line with the other records she found for her family history.
"The estimates for my own antecedents are certainly closer based on my research," said Thurgood-Johnson. "But, you really have to take the DNA analysis with a grain of salt."
Thurgood-Johnson researches her own family history and has helped others do genealogical research for more than a decade. She explained that the key to discovering meaningful family stories was really combining "old-fashioned" research techniques, such as document tracking and discussion with family members, with additional information be derived from DNA test results, such as those provided by Ancestry.com.
"Finding a good paper trail is a great way to start," said Thurgood-Johnson. "That, and finding parents as distant cousins who can offer more information and insights, helps you build a bigger picture, a bigger story about who you are."
Thurgood-Johnson noted, from a personal point of view, that the additional details provided by Ancestry.com after updating the results of her ethnicity profile had allowed her to better appreciate her antecedents.
"It definitely extended my family," said Thurgood-Johnson. "I had a deep knowledge of all cultures before, but I can now say," I'm even more Irish, I'm even more African and even more Native American, "it's wonderful and Ancestry could have been for m "help to understand what all together."
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