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Wednesday, November 18, 2009

Phylogeographic Analysis of Paternal Lineages in NE Portuguese Jewish Communities


The establishment of Jewish communities in the territory of contemporary Portugal is archaeologically documented since the 3rd century CE, but their settlement in Tra´s-os-Montes (NE Portugal) has not been proved before the 12th century. The Decree of Expulsion followed by the establishment of the Inquisition, both around the beginning of the 16th century, accounted for a significant exodus, as well as the establishment of crypto-Jewish communities. Previous Y chromosome studies have shown that different Jewish communities share a common origin in the Near East, although they can be quite heterogeneous as a consequence of genetic drift and different levels of admixture with their respective host populations. To characterize the genetic composition of the Portuguese Jewish communities from Tra´s-os-Montes, we have examined 57 unrelated Jewish males, with a high-resolution Y-chromosome typing strategy, comprising 16 STRs and 23 SNPs. A high lineage diversity was found, at both haplotype and haplogroup levels (98.74 and 82.83%, respectively), demonstrating the absence of either strong drift or founder effects. A deeper and more detailed investigation is required to clarify how these communities avoided the expected inbreeding caused by over four centuries of religious repression. Concerning haplogroup lineages, we detected some admixture with the Western European non-Jewish populations (R1b1b2-M269, 28%), along with a strong ancestral component reflecting their origin in the Middle East [J1(xJ1a-M267), 12%; J2-M172, 25%; T-M70, 16%] and in consequence Tra´s-os-Montes Jews were found to be more closely related with other Jewish groups, rather than with the Portuguese non-Jewish population.

The Portuguese NE Jews display a much closer genetic relation to Jewish populations of Europe and the Middle East, especially other Sephardic groups, than to the Portuguese population. However, it should be pointed out that the high frequencies of haplogroup R1b1b2, less frequent in other Jewish populations, indicate a significant level of admixture with non-Jewish Iberian populations.

Wednesday, November 11, 2009

Family Tree DNA's Walk the Y yields new SNP's for Haplogroup J2

A program by Family Tree DNA, Walk through the Y, was set up late last year to allow customers to search for new SNP's or branches to their respective Y-DNA haplogroups. Recent testing on a number of Haplogroup J2 participants has yielded 9 new SNP's, many of which will prove to be phylogenetically informative in branching current subclades. Below is a list of SNP's found to date:
  • L207.1 A6813448G found in J-L70 and J-L25 participants. May be synonomous with J-L24 or L25.
  • L210 A15001591T found in one J-M67 participant.
  • L212 T21120853C found in J-M67 and J-L25 participants.
  • L218 deletion at 20199329 found in J-M67 participant.
  • L227 C6919963T found in J-M67 participant.
  • L228 C7831358T found in J-M67 and J-L25 participants.
  • L229 C6813447T found in one J-L25 participant, ancestral in another.
  • L230 G20327921A found in one J-L25 participant, ancestral in another
  • L231 C13524835G found in one J-L25 participant, ancestral in J-M67.

It is likely more SNP's will be found as a more thorough analysis of the results has yet to be done. Also, results from other J2 participants have yet to arrive. SNP's can be used to determine the branchin within the Y-Chromosome tree and it is likely some of these SNP's will determine new terminal branches under J-M67 and J-L25.