An analysis of eight Alu insertion loci (ACE, TPA25, PV92, APO, FXlllB, D1, A25, and B65) was conducted in six populations from the Caucasus, which is the region on the border between Europe and west Asia, between the Black and Caspian Seas).
The six populations in the study were Indo-European-speaking Armenians; Altaic-speaking Azerbaijanians; North Caucasian-speaking Cherkessians, Darginians, and Ingushians; and South Caucasian (Kartvelian)-speaking Georgians. As indicated, the Caucasus populations have a high degree of linguistic diversity. This makes the populations of the region ideal for studying the genetic structure in relation to linguistic diversity and geographic barriers, the major one being the Caucasus Mountains. Findings indicate that the Caucasus populations exhibit, on average, less variability than other populations for the eight Alu insertion polymorphisms analyzed. The average heterozygosity is less than that for any other region of the world, with the exception of Sahul. Within the Caucasus region, Ingushians have much lower levels of variability than any of the other populations. The Ingushians also showed unusual patterns of mtDNA variation compared with other Caucasus populations. This indicates that some feature of the Ingushian population history, or of this particular sample of Ingushians, must be responsible for their different patterns of genetic variation at both mtDNA and Alu insertion loci. In contrast to the low levels of variation within Caucasus populations, the populations examined had high levels of between-population differentiation. This is indicative of small, isolated populations. The study found no significant correspondence between the geography of linguistic diversity and the genetic relationship of Caucasus populations. The lack of correlation of genetic relationships with either geographic or linguistic factors further supports the influence of small population size and genetic drift on the genetic structure of Caucasus populations. 2 tables, 3 figures, and 24 references