Why do DNA Companies update their Data Bases?

An interesting thing that has been a recent topic for discussion has been DNA testing updates. AncestryDNA and 23AndMe have both been updating clients with new information as their databases have been updated and have increased in content.  What is there to update?

When a company updates a client’s results and the results change, it is usually because they have tested a broader range of populations or tested more individuals from their existing regions. Some of these companies make it clear that while your origins do not (and cannot) change, results can.

A hypothetical example of changes someone might see is an ethnic Lithuanian, who took a test at AncestryDNA that originally came back at 93% “Europe East”. Now, “Europe East” encompasses a large region which includes Lithuania, but can go as far North as Estonia, and as far south as Croatia. The company does however, have a population specific to “Lithuania”, so it would likely point this out. On top of that, with updates, the service has now added a “Baltic States” region in their population database, differentiating the Baltics from some of their Slavic neighbours. This same Lithuanian may get an update that the original 93% of “Europe East” DNA, is now recognized as 88% from the Baltic States, and 5% from Europe East, and the company would likely pick off some hypothetical Polish ancestry. Likewise, on 23andme, what would have shown the same person to be 93% “Eastern European”, may now continue to show “Eastern European” at 93%, but extrapolate what this “Eastern European” is likely comprised of, within their new tested populations. Now, they may show similarities to the Lithuanian population, so it would be indicated that they likely had relatives from Lithuania at some point in their family history. Hypothetical Polish ancestry would likely be indicated, albeit at a weaker percentage compared to their predominant Lithuanian ancestry.

This is just one example of many new populations and samples having been added to databases. This is significant, as it shows us that testing is improving, and people now have a chance to get more detailed and specific information about themselves than they ever did before.