Because of the geographic peculiarities of the Caucasus, study of its human populations offers an opportunity to assess the influence of geographic barriers on their genetic structure. Previous publications, based on mitochondrial DNA (mtDNA) data, have shown that genetic relationships reflect geographic rather than linguistic relationships [1-3]. Despite the presence of the Caucasus Mountains as a potentially significant barrier to gene-flow, considerable correlation between pairs of geographically-distant populations has been observed [2,4]. Also, these mountains had no detectable influence on the genetic structure of the Caucasus populations [3]. These results led to the proposal of genetic drift as the major factor influencing the genetic structure of the Caucasus populations [5,6]. An analysis based on mtDNA and Alu-insertion data has also shown, that the Caucasus populations are more similar to European rather than to western Asian populations, whereas Y-chromosome analysis revealed a closer relationship to the latter populations [3,5]. Mitochondrial DNA and Y-chromosome-based analyses have also shown an affinity of Caucasus populations with Near East [5,7].

      The Alu family of short interspersed elements is a relatively stable autosomal polymorphic marker with a unique mutational mechanism, for which the ancestral state is the absence of Alu insertion. Because it reflects both maternal and paternal history, an Alu insertion polymorphism is a highly informative tool for studying the genetic structure of human populations [8].