Would it be crazy to call Judaism in 1920s Germany basically like a German subculture of people who are ethnically German and speak a variation of the language? I’ve met so many other Jews (that fled Germany originally) that to me are basically German (even have German last names).
It would be ahistorical, at least: many of the Jews in 1920s Germany had fled pogroms in Ukraine and Russia just 20 or 30 years prior. Many were not particularly integrated, and only spoke Eastern Yiddish dialects.
(The Jews who were already in Germany prior were much more assimilated and less religious than their Eastern counterparts, which is why they often have more Germanic names. This appears in other forms across European Jewry, e.g. Litvaks, being more Western, typically being less religious and more assimilated than the Galitzianers.)
Ashkenazi Jews are not ethnically German. Genetic studies estimate them to be roughly 45% Levantine, 45% Southern European, and 10% Slavic. Germans are 100% North-Western European.
It looks like there's a mixed consensus on ancestry, but a fair bit of evidence they at least intermixed with European locals since prehistoric times [0]
To be clear, that paper is not arguing Jewish ethnic groups were intermixing with European locals since prehistoric times, it is arguing that the Ashkenazi Jews (or perhaps it would be better to say: the proto-Asheknazi Jews) assimilated lots of European converts with ancestry in Europe dating back to prehistoric times.
How do estimates of genetic origin relate to ethnic affiliation? Ethnicity is about culture, customs, and language, not genetics.
As far as genetics go, it's worth pointing out that there's a bit of question begging involved in identifying specific genetics with regional cultural groups in the first place.
Genetics are a poor proxy for ethnicity. There are many who would even refer to the use of blood quantum (e.g. 23-and-me) to determine ethnicity as a form of race (pseudo)science.
I’m curious how they assign percentage to geographic location. For me it fails the sniff tests. Like how far back do you pick your line of ancestry (which has migrated all over the world) when you say stop and determine, this is the place 20% of my bloodline is from?
I imagine they do some sort of cluster analysis to find correlation along with self-identification. If so, then this is undeniably junk science based on junk-in junk-out statistical models (which is often the case with cluster-analysis).
I’m simply curious here, cluster analysis is the only method I can think of (other than guessing/categorizing arbitrarily).
I don’t think the ancestry tests compare the DNA with archeological finds. If they did I wouldn’t trust it given the relatively small sample size of archeological finds with intact DNA.
I thought those were done to investigate migratory patterns, movements, and inter-connectivity of historic populations, not to establish ancestral lineage of living population, and certainly not to assign a geographical region to existing ethnic groups.
Yeah I think it's clustering and dimensionality reduction. E.g. if French people form a rough cluster in DNA space and Japanese people form another cluster, someone with a French mom and Japanese dad would show up as a data point roughly halfway between those two clusters.
I went on a little Wikipedia expedition hoping to find the methodology (and failed), but I did find an interesting (though not surprising) quote from one scientist (Adam Rutherford): “[These tests] don’t necessarily show your geographical origins in the past. They show with whom you have common ancestry today.”
So when our thread’s ancestor (pun unfortunate) says “45% Levantine” they mean they 45% of people alive today that are from that region (which includes many European immigrants). I bet this gets very messy given immigration patterns. Like which immigrants count as ancestry sample, and which don’t? For this problem I would personally use cluster analyses, however I would probably simply give up, knowing that cluster analysis would give me junk (and ultimately arbitrary) results with such noisy (and potentially skewed) data.
EDIT: The answer was right there next to this quote, in one of the aside picture for the same article[1]. They use Principal Component Analysis. Which IMO is even more fraught than cluster analysis, as you have even more control over what you want to get out of the model. If I remember correctly PCA—along with factor analyses—is used heavily in personality psychology and intelligence testing, the latter of which is very famous for radicalized pseudo science.
My understanding of ethnicity on a genetic level is basically that it's the degree of relatedness above "clan", e.g., you have something of a hierarchy from: individual > family > clan > ethnicity. What's the issue with declaring some sufficiently high degree of relatedness ethnicity? Or is relatedness that diffuse not measurable?
It is not that genetic simmilarity is inherently meaninglessness. Just that it is not a good proxy for the social concepts people are generally using it to talk about.
The amount of assimilation was not homogeneous anywhere in Europe. In urban environments, some Jewish families were highly assimilated, and there was a great deal of interaction between Jewish people and Gentiles. If these dynamics are interesting to you, you might want to read about the haskalah:
Out in the stetls (in rural towns), there was far less assimilation (although a lot of interaction). For example, in Poland prior to WW2, Jewish society was almost a parallel world. Polish Jews had their own religious institutions, shops, and, at various times, a parallel government. For centuries, Poland was like two separate worlds that inhabited the same physical space.
It's really too bad that it ended. I grieve for something I never even knew.
_PC_analysis.png){kind=link}