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Abstract
We examined genetic variation in nine populations of Dagestan using 11 autosomal Alu insertion polymorphisms to investigate the genetic structure of indigenous groups and to assess their genetic relationship with world populations. Genetic differentiation among mountain inhabitants (G^sub ST^ = 2%) is comparable to that for European populations. Traces of genetic drift are detectable only for endogamous and small Ando-Dido-speaking ethnic groups, and they coincide with the most linguistically diverse region of Dagestan. Multidimensional scaling analyses among West Eurasian populations revealed that mountain inhabitants of Dagestan are closely related to Anatolian and Cyprus Turks. Thus our frequency data are consistent with the available Y-chromosome data, according to which the Middle East and the Caucasus share a considerable portion of the gene pool. Overall, our results corroborate the initially suggested genetic contribution of Middle Eastern populations to Caucasus populations.
KEY WORDS: POPULATION GENETICS, GENETIC STRUCTURE, ALU INSERTION POLYMORPHISMS, DAGESTAN, CAUCASUS, RUSSIA.
The Republic of Dagestan is located in the eastern part of the North Caucasus and is bordered by the western coast of the Caspian Sea. This eastern Caucasus republic is the most linguistically diverse region of the Caucasus and is composed of more than 30 ethnic groups. These ethnic groups can be subdivided into mountain and steppe inhabitants. Although most mountain inhabitants speak Northeast Caucasian (Nakh-Daghestanian) languages, steppe inhabitants, represented by Karanogays and Kumyks, speak Turkic languages. Northeast Caucasian speakers are considered descendants of the ancient indigenous tribes (Gadjiev 1972) that probably introduced the early agricultural tradition in Dagestan (Osmanov 2002). According to recent estimates, the Northeast Caucasian language family, which is geographically restricted to the Caucasus, is about 6,000 years old (Nichols 2003).
The mountain-residing indigenous populations are characterized by an elevated endogamy rate (Bulayeva et al. 2003a, 2003b; Gadjiev 1972). The steppe inhabitants differ from their neighboring mountain inhabitants both by their recent appearance and their rates of consanguineous marriages. For example, Karanogays are descended from various Turkic-speaking nomads of Central Asia, but there is still no common consent on the origin of Kumyks (Osmanov 2002).
Data on mtDNA and Alu insertion variation in Dagestan populations are already available (Bulayeva et al. 2003a, 2003b). Both the mean pairwise divergence of Dagestan mtDNA sequences and the high mean AIu frequencies suggest...