A reader sent me a link to this article which concludes: “This contrasting pattern of diversity in Ashkenazi populations is evidence for a reduction in male effective population size, possibly resulting from a series of founder events and high rates of endogamy within Europe.” Fine and dandy, but I just keep recalling this article in Discover from 1995 which made many simlar points, it pointed out that the majority of Hungarian Jews in any given generation were paupers, and that wealthy mercentile and rabbinical families were the ones that had high fertility rates and perpetuated the Jewish people (through historical research of records). In other words, a small effective population size….

Excerpt below….

Update: Henry cautions me about relying on one locus (the Y chromosome). I guess I will make my assumption explicit for readers-when I post links to papers like this, I don’t expect them to be definitive, rather, over the years, the multitude of studies will form a composite understanding of the history of various parts of the genome (especially nonrecombining regions like the Y & mtDNA obviously). The current methods of historical genetics just keep getting better, when I was in college I remember reading papers that talked about the problems with distinguishing between the Irish and Norwegians, as the noise overwhelmed the ability to distinguish the two groups statistically. This isn’t true anymore it seems. Those who have ideological axes to grind will cherry pick from the studies to “prove” their points, that’s not my intention, rather, each study is just another data point in a portrait that is only beginning to be clear.

Admixture estimates
Table 6 shows the haplogroups with the highest frequency differentials between European non-Jewish and non-Ashkenazi Jewish (Hammer et al. 2000) parental populations (see above) and a summary of the admixture estimates for AJ populations. Among the western AJ populations, haplogroups J-12f2b* and R-P25 were the most diagnostic for distinguishing the parental Jewish (P1) and the parental western NJ European population (P2W) components. Among the eastern AJ populations, haplogroups J-12f2b* and R-M17 were the most diagnostic for distinguishing the parental Jewish (P1) and the parental eastern NJ European population (P2E) components. All other haplogroups had values below 20% (data not shown). When these diagnostic haplogroups were used for analysis, the m y value was 8.1%±11.4%, suggesting an even smaller contribution of European Y chromosomes to the Ashkenazi paternal gene pool than in the previous study by Hammer et al. (2000). Because of the apparently high level of admixture in Dutch Jews (m y value of 46.0%±18.3%), we repeated the admixture calculation excluding the Dutch sample and found a lower estimate of admixture (~5%). Although not statistically significant, there was a higher level of admixture in eastern AJ versus western AJ populations. This is similar to differences in the levels of mtDNA introgression observed in western and eastern AJ populations (Behar et al. 2004).

[. . .]

Discussion
This survey of variation at 32 binary (SNP) and 10 STR markers in a sample of 442 Ashkenazi males from 10 different western and eastern Europe communities represents the largest study of Ashkenazi paternal genetic variation to date. In a previous study by Hammer et al. (2000), a set of 18 SNPs was typed in a diverse Jewish sample that included 113 Ashkenazim from the US (the European provenance of these samples was unknown). This AJ sample was characterized by nine haplogroups that were also found in several other Jewish populations. Similarly, studies by Nebel et al. (2001) and Thomas et al. (2002) have included a modest Ashkenazi sample (i.e., 25%) and I-P19 (>10%). These results are not surprising in view of the longstanding religious tolerance in this region. However, Dutch Jews do not appear to have increased levels of European mtDNA introgression (Behar et al. 2004), suggesting that admixture in this population is mainly the result of higher rates of intermarriage between Jewish woman and non-Jewish men.

Posted by razib at 10:42 PM