Sunday, August 1, 2021

Understanding Admixture and Genetic Overlap at AncestryDNA

I talk a lot about the genetic overlap that exists among neighboring regions and how that influences ethnicity percentages, or admixture. Unfortunately, AncestryDNA keeps taking away valuable learning tools for understanding these relationships between various populations, making it harder to illustrate them. First, they removed the Average Admixture Chart, then they removed the Genetic Details page, and now they've even removed our ability to click on "see other regions tested" and explore the maps and details of any region to understand the overlap they have with neighboring regions. The only thing left is the PCA chart in the Ethnicity White Paper, but even that has always been limited to Europe. 

The Average Admixture Chart (below) used to show us what the results of a typical native of every region would expect to get. It showed how much or how little each population was admixed. So for example, if you were of 100% British descent, you could expect to actually only get about 60-70% in Great Britain (this was before they decided to attempt to split up Britain), and around 8-10% in Europe West, Ireland, and/or Scandinavia. This illustrated the common overlapping DNA among the British, Germanic people, and Scandinavians, and also the close relationship between the British and Irish (sorry, Ireland). Europe West was even more admixed, averaging less than 50% results in Europe West, and the rest coming from pretty much everywhere else in Europe except Finland/NW Russia. Scandinavia was less admixed, averaging between 80% to 90% in Scandinavia, and only small amounts from Europe West, Great Britain, Finland/NW Europe, Ireland, and a smidge from Europe East. The chart made it clear just how admixed Europeans themselves are, or can be, and to AncestryDNA, that is apparently a bad thing that they are now trying to hide, because it means ethnicity percentages, by nature, are always very reliable, and can't always be broken down into more specific regions. That's something customers are frustrated by, so one by one, they keep taking away the learning tools that would help customers understand this.

The loss of the Average Admixture chart wasn't too unfortunate, because the same/similar data could essentially be found on the Genetic Details page. Previously, when you clicked on a region, and then clicked "More info", there would be a page with two tabs - one which still remains with the detailed history of the population and their migrations, and the other had genetic details that helped us understand the genetic overlap that region had with nearby regions. That second page is now gone. It showed us two very important charts that basically replaced the data in the Average Admixture chart. The first one (below) showed us the average percentage that a native of that area would likely get for that region (same as you would find on the Average Admixture chart). 

The second chart (above) showed us "Other regions commonly seen in people native to [this region]". This wasn't exactly the same data from the Average Admixture chart - it rather detailed the amount of people native to that region who got any amount of results in which neighboring regions. So it didn't tell us the amount a native would expect to get in those other areas, but how common it was for a native to get results in those other areas. Not exactly the same data, but still valuable data for understanding common overlap.

With these two vitally important learning tools gone, I often turned to the simple map and details of each region to illustrate how each region often covers neighboring regions as well. If you click on "Read full history" for each region, you can find not only the areas "primarily found" in that region, but the areas "also found in" that region too (above). Unfortunately, AncestryDNA has neglected to add the "Read full history" link to some of the newer regions (like Scotland) they added recently! An oversight? Or an indication they may also be retiring this page altogether now too? And on top of that, a new revamp of the appearance of our ethnicity results (may not be available to everyone yet) seems purely aesthetic at first, until you notice the link to "See other regions tested" is now gone too (below). 

It's as though they don't want people to understand how much genetic overlap there is between certain regions, even though it would greatly help people to understand their results. And now, anytime people ask, "If I get results in X, is it coming from my Y ancestry?" and it's not a region I have results in, I can't answer them because I can't look up the map and details of regions I didn't personally get results in. This kind of question gets asked so frequently in social media, and frankly, people like me basically wind up fielding these questions for Ancestry's customer support, and they keep making it more and more difficult. I guess if they really want a huge increase in the load on their customer support, that's fine, but if that's the case, they really shouldn't have gotten rid of their support email (you can now only contact them by phone, or social media like Facebook). So, they're making it harder for customers to understand their results, and harder for customers to contact them about it. Epic fail on customer service, AncestryDNA.

The only remaining tool is the PCA chart (top), which is limited to Europe and therefore not much help in understanding results outside of Europe, or any relationships that might exist in the crossroads between Europe and other continents. And frankly, I have some concerns that voicing this will lead to them to remove the PCA chart too.

The percentage range included in our results is also useful for understanding that the percentages are very much an estimate, but not very useful for understanding the genetic overlap between regions. Still, hopefully they don't retire this feature either, but the ongoing trend doesn't bode well for it. 

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