One of the hobbies that I spend far more time doing than writing about is examining my genetic genealogical relationship to others. Sometimes this means finding out how I am a distant cousin to strangers whose family roots are immensely complicated, but most of the time this means matching myself to various ancient peoples who have been dug up and whose genes have been tested. Sometimes the results of that are quite fascinating, and I would like to talk about two such sets of examples that raise interesting questions to me about how it is that Genetic Genealogy operates among large companies and the gaps between what we can know about our genealogy and what we can know about our larger background.
Earlier today, as I write this, some acquaintances of mine online shared some DNA samples that have recently been studied concerning the Philistine invasion of the Levant. As a student of biblical history, of course, I have long studied the Philistines, but it was very surprising and striking to me to find that I share a substantial amount of DNA with some of the early Philistine settlers of Ashdod. How is this so? The numbers are far too large to be accidental, ranging between 1 and 3% or so of my entire background. How did a sizable amount of my ancestry end up being Philistine, and where did it connect to my background at present? There has to have been some sort of story–am I descended from Philistines who converted to biblical religion and were part of David’s bodyguards, or what? To be sure, I have no genealogies that go back to that point, and it remains rather striking and unusual that it could be obvious that I have background going back to the crisis of the late Bronze age and the settlement of Philistia from Aegean sources and not know anything about how that family line came to join with other backgrounds.
A similar thing happened recently when I looked at various ancient indigenous American DNA results and found a small but traceable amount of ancestry going back to various ancient peoples who migrated into North America and were among the earlier settlers of North America. Here too there is a mystery of how this DNA connects with my own. Which ancestors of mine married into local Native American tribes? What are their stories? What tribes were involved in this, as it almost certainly happened at some point during the colonial period? The genes don’t lie–there is some connection there–and yet that connection does not tie to a traceable record that I have at present. And, it should be noted, in neither case do DNA companies trace this sort of ancestry back through anything in particular, even though especially in the Philistine case a large amount of DNA is involved.
There are definitely gaps here. How do we get from the point where can trace clear ancestry to individual samples with whom we have no paper connection to knowing what sort of background those people had, and then being able to find out how it is that we connect to these distant sources? At some point one wants a paper trail to work with. Knowing that 3000 years ago some sizable portion of my ancestry was made up of Aegean settlers of a particularly fierce kind (not particularly unbelievable) is certainly enjoyable, or knowing that a smaller part of my ancestry (around 1% or so) settled North America early, all of that is enjoyable to know. But those genes traveled generation after generation before arriving in me. How does one recover that tale?