mtDNA and Y-chromosome variation in the Talysh of Iran and Azerbaijan.

The Northern Talysh from Azerbaijan and the Southern Talysh from Iran self-identify as one ethnic group and speak a Northwestern Iranian language. However, the Northern and Southern Talysh dialects are so different that they may actually be separate languages. Does this linguistic differentiation reflect internal change due to isolation, or could contact-induced change have played a role? We analyzed mtDNA HVI sequences, 11 Y-chromosome bi-allelic markers, and 9 Y-STR loci in Northern and Southern Talysh and compared them with their neighboring groups. The mtDNA data show a close relatedness of both groups with each other and with neighboring groups, whereas the Northern Talysh Y-chromosome variation differs from that of neighboring groups, probably as a result of genetic drift. This genetic drift most likely reflects a founder event in the male gene pool of Northern Talysh: either fewer males than females migrated to Azerbaijan, or there was a higher degree of relatedness among the male migrants. Since we find no evidence of substantial genetic contact between either Northern or Southern Talysh and neighboring groups, we conclude that internal change, rather than contact-induced change, most likely explains the linguistic differentiation between Northern and Southern Talysh.