Although this is as yet only a provisional paper, and I don’t know what, if any revisions will be made, it nevertheless makes several notable observations. It’s free to access, and begins as follows:
In this study, we used genetic data that we collected in Central Asia, in addition to data from the literature, to understand better the origins of Central Asian groups at a fine-grained scale, and to assess how ethnicity influences the shaping of genetic differences in the human species. We assess the levels of genetic differentiation between ethnic groups on one hand and between populations of the same ethnic group on the other hand with mitochondrial and Ychromosomal data from several populations per ethnic group from the two major linguistic groups in Central Asia.
Our results show that there are more differences between populations of the same ethnic group than between ethnic groups for the Y chromosome, whereas the opposite is observed for mtDNA in the Turkic group. This is not the case for Tajik populations belonging to the Indo-Iranian group where the mtDNA like the Y-chomosomal differentiation is also significant between populations within this ethnic group. Further, the Y-chromosomal analysis of genetic differentiation between populations belonging to the same ethnic group gives some estimation of the minimal age of these ethnic groups. This value is significantly higher than what is known from historical records for two of the groups and lends support to Barth’s hypothesis by indicating that ethnicity, at least for these two groups, should be seen as a constructed social system maintaining genetic boundaries with other ethnic groups, rather than the outcome of common genetic ancestry
Our analysis of uniparental markers highlights in Central Asia the differences between Turkic and Indo-Iranian populations in their sex-specific differentiation and shows good congruence with anthropological data.
Reference: Evelyne Heyer, Patricia Balaresque, Mark A Jobling, Lluis Quintana-Murci, Raphaelle Chaix, Laure Segurel, Almaz Aldashev and Tanya Hegay. Genetic diversity and the emergence of ethnic groups in Central Asia. BMC Genetics, 2009; (in press) [link]