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One man sent nine samples of his DNA to three different companies and he received six different results. Rafi Letzter, a writer from Live Science, sent his DNA to AncestryDNA, 23andMe and Nat Geo, which uses Helix to process the raw DNA while Nat Geo interprets the DNA. Letzter knows he comes from a family with strong Jewish ties but he has never taken a test before. 

AncestryDNA samples:

Three samples were sent, all under different names but only two got processed, as one resulted in an error preventing him from accessing his results. 

First sample:

Second sample:


23andMe Samples:

Letzter sent three samples to 23andMe. At first, two samples both reported low 90s (percent) in the Ashkenazi Jewish origin. The third sample was sent under a female name and was labelled as female, even though Letzter is a male. The sample was processed fine but 23andMe asked for more personal information since the sample came from someone with "unexpected chromosomes." However, while reporting on this story, 23andMe updated its DNA interpreting system, meaning it reassessed all of the DNA already in it system. After the update, the reports came back as 100 percent Ashenazi Jewish. 

Nat Geo and Helix:

Again, three DNA samples were sent to this company for testing, but only two were successful in retrieving results. 

First sample:

Second sample:

As you can see, this company found that Letzter was significantly less Ashkenazi Jewish than the previous two companies.


Why does this matter? And how does this happen?

Well, it kind of doesn't matter, and it happens for a number of reasons. The reason for population genetics is to focus more on where groups of people moved and when. Ancestry isn't an exact science since humans have never been exact/hyper-distinct groups of people. According to the article, "To divide people into groups, Platt told Live Science, researchers make decisions: For example, they'll say, the members of this group of people have all lived in Morocco for at least several generations, so we'll add their DNA to the reference libraries for Moroccans. And people who had one grandparent with that sort of DNA will hear that they're 25 percent Moroccan. But that boundary, Platt said, is fundamentally 'imaginary.' 'There is structure to history,' he said. 'Certain peoples are more closely related to each other than to other peoples. And [commercial DNA companies] are trying to create boundaries within those clusters. But those boundaries never really existed, and they aren't real things.'"

What could this mean for the future of commercial DNA testing companies?

This lack of certainty could cause a drop in consumer faith in the products. If you can send in nine different samples and get six different results, it'd be hard to be sure which report, if any, you should believe. Also, as we heard in class, 23andMe is now going to test how you respond to certain medications. Well, if their ancestry data is so subject to error, how can the reports on medication response be trusted? That's certainly something 23andMe can't afford to be wrong about. 



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