Angela said:
Jews were living in what is now Poland and surrounding areas for 1200 years.
Rather since 1200 AD, not for 1200 years. I'm not sure if they were already in Rhineland 1200 years ago, let alone Poland.
AFAIK, Ashkenazi bottleneck took place while they were in Rhineland (or even earlier), before moving eastward.
Some Jewish travellers and merchants visited this part of Europe (and even described it - see
Abraham ben Jacob) as early as the 900s, but there is no evidence that any of them settled in the Poland at that time. Even if a few of them settled, those were just individuals, not organized communities with synagogues. First Jewish communities started to appear in Poland in the 1100s - 1200s.
However, until the end of the 15th century the share of Jews among the population of Poland-Lithuania amounted rather just to promiles. Their share surpassed the threshold of 1% during the 16th century, with immigration of Jews expelled from Germany.
Since 1500s until 1900 the share of Jews was increasing from 1/100 at the beginning to ca. 1/10 by the end of this period.
Times when Jews formed a really large portion of the total population of Poland-Lithuania, lasted a few centuries.
BTW - the earliest Jewish communities in Poland were Slavic-speaking (they spoke a language known as
Leshon Knaan). Only later as the result of mass immigration of Jewish refugees from Germany, the whole Polish-Jewish Diaspora became Yiddish-speaking.
Maybe more intermarriages between Jews and Gentiles took place in early times, when local Jews spoke Leshon Knaan.
Perhaps some of those Slavic-speaking Jews assimilated into Gentiles, rather than into Yiddish-speaking immigrant Jews?
Angela said:
Didn't the Hellenthal/Busby group pick up something from the Near East into Poland (or Eastern Europe in general) through their IBD analysis? I didn't think it made sense, and I'm unconvinced they have the timing right for these supposedly "recent" admixtures, but could that have something to do with this score for Poland? It never occurred to me at the time we were discussing it.
When it comes to the Near East - there were for example significant migrations of Armenians to Poland. Those Armenians were less endogamous than Jews, more prone to assimilation with the mainstream culture, and melted into local populations.
Angela said:
Do you remember if the Behar study on Ashkenazi IBD quantified gene flow into Poles?
I don't remember, but I will check.
Angela said:
At the beginning of that time if I'm not mistaken some areas weren't even Christian yet and intermarriage wasn't prohibited
But endogamy is part of Jewish tradition, and it is like this already since Ancient times, before they left the Holy Land.
Those weren't [only] Christian laws which prohibited Jews from marrying Non-Jews, but those were Jewish laws [too].
Even today intermarriages between Orthodox Jews and Non-Jews are extremely rare, both in Israel and in the USA.
Well, in Israel even Non-Orthodox Jews very rarely mix with Arabs.
There was even a case in Israel when an Arab told a Jewish woman that he was Jewish, then they had consensual sex, but when she learned that he wasn't really Jewish, she accused him of "rape by deception", because he had lied about his ethnicity.
Angela said:
I would hardly take the word of someone with such a history of virulent anti-Semitism
What exactly is so anti-Semitic about Davidski?