Genetic Groups on MyHeritage - 1 First Thoughts

 

MyHeritageDNA have introduced 'Genetic Groups', a new feature which I think could have a huge impact on our understanding of Ashkenazi Jewish (AJ) history in general, and of our own families' histories in particular. The same will undoubtedly apply to other groups across the world.

MyH has published an account of how they have put these Groups together. Briefly, they base them on the segments of DNA, including very small ones, that you share with other people. These patterns of shared segments can be regarded as the signature of a Genetic Group. These shared segments must have come from a common ancestor, who may well date from long before any of the ancestors that most of us can trace by traditional genealogical methods. MyH then combines this shared segment information with the historical and geographical information contained in those people's Family Trees.

This technique will not point directly to a specific common ancestor, but the fact that you share a Genetic Group with someone should help narrow down the field, and may suggest likely areas for further research. It should eventually provide a more reliable, and potentially much more informative, indicator of ancestral origins than merely looking at shared matches, or vague "ethnicity estimates". 

My Genetic Groups

The map above shows the geographic reach of the 5 AJ Genetic Groups that they have found for me, based on shared segments and the date and place information my matches have included in their Trees. Of course, not everyone has a full Tree, but when the numbers of people providing this information are high enough, MyH can begin to see patterns emerging. These patterns show that people who match me on particular segments tend to have ancestors that come from particular geographic areas.

You can see immediately from the map that these Genetic Group areas cover distinct territories. There are two Groups in smaller regions that have a definite western bias, running from the Netherlands across to Poland; one of these reaches a bit further north than the other. Another Group has an eastern bias, reaching from Poland to central Russia. One of the Groups seems to cover much of the map, stretching most of the way across from Germany to Ukraine. The fifth Group is centred in the East, across Belarus and Lithuania. My matches in each of these Genetic Groups share a DNA signature with me that corresponds with these areas of origin. You can almost see the Litvaks and the Polacks peeking through.

My mother's parents both came from central Poland, and my father's from various places in Belarus. Jews came into these areas from Western Europe during the Late Middle Ages, moving gradually eastward over a period of several centuries. You can sense the pattern of this migration even in the roughly-drawn areas on this map. I have documented Trees back to 1800 or so for the male lines of the families of each of my four grandparents, but I do not as yet know where any of these families were living before they moved east, nor when they moved. Any source that can suggest answers to this is worth looking at.

My initial thoughts are that a common ancestor for me, with someone who is in one of the more western groups, will probably date from medieval times, and will be correspondingly hard to trace. Matches from the two groups that cover the eastern areas may well trace back to more recent times. My Polish matches could come from any of the five groups, as the map shows that all five of them include the central part of Poland.

I'll be looking more closely at my five Genetic Groups, from the geographical, historical and genetic perspectives. What can they tell me about the stories of my ancestral families?

NB: Roberta Estes has posted an excellent guide to using this feature, on her DNAeXplained site: Introducing Genetic Groups at MyHeritage