Thursday, 5 October 2017

Tracing the X in Levin

Several of my cousins have now done a DNA test, and we are beginning to get some interesting results. Within the last couple of weeks results have come in for Beatrice, a 3rd Cousin to me, and for Dan, a 2nd Cousin. Dan and I share great-grandparents, Shliomo Dovid Ilyutovich and Mikhlya Levin, whilst Beatrice's great-grandfather is Mikhlya's brother Leib. So our connection with Beatrice is one generation further back, with the parents of Mikhlya and Leib, Berko Levin and his wife Sora Leya. Our Levin family is from a village called Streshin, in Mogilev province in the east of Belarus, and later from Gomel, a bit further south.

With these new results in, I was able to do a few checks comparing known Levin family members using the chromosome browser on the FTDNA website. Apart from my brother Brian and myself, we have results for Katy (the daughter of our 1st cousin Jenny, so she's our 1st Cousin-once-Removed), and for Patrick - a 1C1R to Dan. 

The Chromosome Browser shows us where we have segments of DNA that exactly match those of another person. These matching segments - especially the longer ones - must almost certainly have come from a common ancestor, although in many cases this ancestor will turn out to be too far back in time for us to be able to trace.

The first impression was that we all seem to match each other here and there, to a greater or lesser extent. Phew! I experimented comparing the group first against myself, then against Brian, then against Katy - and it was here that I encountered a major surprise.

Here is the chart for Katy's X-chromosome. The X has a different inheritance pattern to all the other chromosomes. It is passed from the Mother to all children, Male & Female, and from the Father only to a Female child. This makes the inheritance path quite complicated, but if you sit down with the Tree in front of you and a pencil in your hand, you can follow it through.
NB: the black background represents Katy, the green is Dan, the yellow is Beatrice. The blank lines you can discern on the right-hand side are where Brian, Patrick and myself would be, except we didn't get this X because we are all males, and our Levin line passes through our fathers. And as we saw above, fathers don't pass an X on to their sons. And none of us matches Katy on the left-hand side.

We see that Dan shares a long segment on the X-chromosome with Katy, and Beatrice also matches both of them in this segment in a couple of short stretches. Dan's match with Katy is 110cM, which I am told is unusually long for 2C1R - the segment has been passed down unaltered over 3 generations to Dan, and 4 to Katy. And although Beatrice's match is comparatively short, it is significant that she matches with both of the others at those points.

What is more, we know where this segment comes from, for any ‘match’ displayed in the Chromosome Browser has to come from an ancestor common to all the people who share the match, and our cousinship is close enough for us to know who those ancestors are.

We can trace one of Dan’s X-inheritance paths back via his mother Raya, and her father Shmuilo, to our great-grandmother Mikhlya Levin, and then on to her mother Sora Leya, born about 1830. 

Katy has a path that also wends its way back to the same place, via her mother Jenny, Jenny's father Michael, his mother Zlata, and back to Mikhlya and on to Sora Leya.

And Beatrice also has one that goes back to Sora Leya, via her mother Alice, Alice's mother Annie, and Annie's father Leib, Mikhlya’s brother.

Here's our Levin X-inheritance chart:

NB: girls are pink, boys are blue; and notice that none of these 3 paths pass through two successive males at any point - this would block transmission of the Levin X, which is why Patrick, Brian and myself can't share in the fun.

So we can trace this long stretch of X back to a known common ancestor. That in itself is nice to know, but it has further significant potential. Because anyone else matching Dan or Katy on that same stretch of X - or Beatrice, on her shorter stretch - will have got it from Sora Leya, or from her X-path ancestors, or their X-path descendants. That leaves quite a lot of possibilities, but at least we know what direction to look in.

I would say that this makes anyone matching either of Dan or Katy on the right-hand module of the X-chromosome worth following up - they will be related to us, and the relationship may be traceable. They won’t be close to us, the closest they could be is probably descendants of any siblings of Mikhlya and Leib - but it would be wonderful if we do find some! They would be 3rd Cousins to us - and that's worth knowing about!

Dan and Katy meet for the first time last year. At that point we didn't know about the X in Levin.

Two more members of the Levin X-club: Beatrice and Alice, celebrating Alice's 100 birthday in 2011 with a Yiddish song or two. Sadly Alice passed away the following year.

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