On The Problem Of Populations In Genetic Genealogy

One of the notable aspects of genetic genealogy is the marketing that companies push to would-be customers about how genetic testing can help one better understand where one comes from. What I would like to share is a bit of a comparison of the results of three separate genetic testing services that all offer the same sort of testing and make similar promises about helping people find their ancestry, and I would like to see if you all can spot the differences in the results obtained by each company. Here is company one, Ancestry.com, where I got my results tested last year for Mother’s Day on the urging of my mother:

Ancestry.com has a large base of customers and is based out of the United States. It is little surprise, given my family tree, that this goes straight back to mostly Northern and Western Europe, and it is interesting to note that there are four source European populations seen here, each of them sending people to early settlers in North America. There are still others that could have been seen, including early New England, New Netherlands, and early Upper Canada/Ontario settlers. But I understand that there are only so many settler groups that they want to link to. Let us note the locations of these four groups as we move on to the next set of results.

It is interesting to note that My Heritage has a large body of customers from the Jewish diaspora and from Eastern Europe, in that it noticed zero English ancestry but instead lumped in the English ancestry in a vague Northern and Western European and also lumped in a fair amount of DNA to various Celtic groups that included Cornwall and Brittany (more on this later). It is especially telling that a website that has a lot of Jewish customers would recognize some of the deeper Middle Eastern and West Asian DNA that would be familiar from other users as well as Eastern European DNA that could come from either Scandinavian or German roots, as we move on to the final set of results, from a testing company that for reasons that will become clear focuses on the British Isles:

What is particularly telling about this particular set of results is that it shows such granularity in Great Britain, and almost all of the places it finds my roots are places that I can find in my family tree and presumably in the records of births, baptisms, marriages, and burials contained in various parish churches around the British Isles. It is interesting that this particular company differentiates between England and Northwestern Europe but lumps all of the “North German” populations together as well as containing different South German populations, all of which I have, but does not include any Scandinavian or Eastern European roots or anything like that, perhaps noting the Scandinavian DNA as having an origin in places like Yorkshire (among others) where Vikings intermarried with the local population.

What is perhaps most remarkable about this wide variety of results is that all of them result from the same DNA sample provided to Ancestry.com and then uploaded to the other two services, which found different results on the same DNA raw data based on their own population data based on who else has included results with them. There are broad similarities–all of the results show my family to be a reasonably well-traveled family of European ancestry that has more going on than meets the eye, none of which would be a surprise to anyone who knows me, nor was it something that surprised me at all. It would be curious, as a thought experiment, to imagine how it is that DNA testing that focused on the population of continental Europe would be able to differentiate between the Northwestern and Germanic and Scandinavian populations to provide some indication of the difference between, say, Swiss German and Volga German populations, or between someone who came from Sweden directly, or a Viking ancestor in North Yorkshire, or a Viking who had settled in Russia?

It is important to note that there is no such granularity at present in genetic testing, and that even the same results can be read drastically differently based on the profile of the people who are in any particular company’s database. Each of the three results offers a snapshot of my family’s ancestry that brings to light different aspects of their travels, showing that I have (perhaps unsurprisingly) a fairly ordinary mix of Northern and Western European ancestry but one that traveled and left a lot of cousins in faraway lands (for example, as I have noted previously, I have some very far-flung genetic connections ranging from descendants of Dutch settlers of Brazil to descendants of Baltic Germans to early settlers of places like St. Helena and South Africa, from Mormons obsessed with their genealogy to African-American descendants of slaves struggling with their own background and its implications. All of these people are my relatives near enough to be recognized as such, and there is not a single database currently present that recognizes this complexity in enough detail to tell the sort of family story that they are selling to customers. Perhaps that will change in due time.

About nathanalbright

I'm a person with diverse interests who loves to read. If you want to know something about me, just ask.
This entry was posted in History, Musings and tagged , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s