I have his address - already emailed him! Besides, I know all the rough details of the bottleneck anyway - just I'm not yet fluent at all in dealing with Y DNA.If the last common ancestor between Gentile and Jew, so to speak (I don't think of people in those divisions!), was about 1350 ybp, why are there so few AJ Y DNA I1s? Surely it would have grown massively in Poland-Lithuania given the birthrates for Jews would have been so high, right? The same applies to some other branches too, but for many of these branches it is likely the ancestor was originally Middle Eastern, so why then aren't there more people in that branch? According to jewishdna.net, at least from gauging the pie chart (it's hard to tell precisely, as I'm definitely not manually counting things up), Y DNA I1 accounts for about 2% of the pre-bottleneck branches, but now it's ten times less that!