Y chromosomes and mtDNA of Daghestan groups

This is a free paper which establishes the difference between highland Northeast Caucasian speakers and lowland Altaic speakers in Daghestan. The lowland groups show evidence of Mongoloid haplogroups in both Y chromosomes and mtDNA, while the highland groups are dominated by haplogroup J:

The highland Avar, Dargin, and Kubachi exhibit high frequencies of haplogroup J (0.56, 1.00, and 0.67, respectively)

According to Table 2, the Avars possess 0.33 of J2, so, consistent with previous observations, the Northeast Caucasian groups are J1 (or at least J*(xJ2)) exclusive.

Interestingly, haplogroup G occurs in the Avars (0.06) but not in the other highland groups. Haplogroup G is common in the Southern Caucasus. The mountain groups also have little R1*(xR1a1) (0.06 in Avars, 0.08 in Kubachi) and no I, R1a1 or E.

It certainly seems to be the case that the highland Northeast Caucasian speakers are descended from a J1-dominated ancient Near Eastern population which was preserved due to patrilocal endogamy. The relationship -that I wrote about earlier- of these Caucasian J1's to the Arabian J1's, the second major region of J1 dominance remains to be seen.

BMC Genetics 2008, 9:47 doi:10.1186/1471-2156-9-47

Culture creates genetic structure in the Caucasus: Autosomal, mitochondrial, and Y-chromosomal variation in Daghestan

Elizabeth E Marchani 1, W Scott Watkins 2, Kazima Bulayeva 3, Henry C
Harpending 1, Lynn B Jorde 2§

Abstract

Background

Near the junction of three major continents, the Caucasus region has been an important thoroughfare for human migration. While the Caucasus Mountains have diverted human traffic to the few lowland regions that provide a gateway from north to south between the Caspian and Black Seas, highland populations have been isolated by their remote geographic location and their practice of patrilocal endogamy. We investigate how these cultural and historical differences between highland and lowland populations have affected patterns of genetic diversity. We test 1) whether the highland practice of patrilocal endogamy has generated sex-specific population relationships, and 2) whether the history of migration and military conquest associated with the lowland populations has left Central Asian genes in the Caucasus, by comparing genetic diversity and pairwise population relationships between Daghestani populations and reference populations throughout Europe and Asia for autosomal, mitochondrial, and Y-chromosomal markers.

Results

We found that the highland Daghestani populations had contrasting histories for the mitochondrial DNA and Y-chromosome data sets. Y-chromosomal haplogroup diversity was reduced among highland Daghestani populations when compared to other populations and to highland Daghestani mitochondrial DNA haplogroup diversity. Lowland Daghestani populations showed Turkish and Central Asian affinities for both mitochondrial and Y-chromosomal data sets. Autosomal population histories are strongly correlated to the pattern observed for the mitochondrial DNA data set, while the correlation between the mitochondrial DNA and Y-chromosome distance matrices was weak and not significant.

Conclusions

The reduced Y-chromosomal diversity exhibited by highland Daghestani populations is consistent with genetic drift caused by patrilocal endogamy. Mitochondrial and Ychromosomal phylogeographic comparisons indicate a common Near Eastern origin of highland populations. Lowland Daghestani populations show varying influence from Near Eastern and Central Asian populations.

Link (pdf)