Open Access Preprint
The analyses of 15 autosomal and 23 Y-chromosome DNA STR loci in five rural populations from the Caucasus, namely four ethnically Georgian and one ethnically Armenian populations, indicated that two populations of Georgians - one from the west and the other one from the east of the Greater Caucasus Mountains - were both patrilineally and autosomally most differentiated from each other, and the other populations of Georgians and Armenians held an intermediate position between those two. This pattern may be due to human dispersal from two distinct glacial refugia in the last glacial period and the early Holocene, followed by less gene flow among the populations from the Greater Caucasus than those from the rest of the Caucasus, where the populations have undergone substantial admixture in historical time. This hypothesis is supported by a strong correlation between genetic differentiation among the populations and landscape permeability to human migrations. The latter is determined by terrain ruggedness, forest cover, and snow cover. Although geographic patterns of autosomal and Y-chromosome DNA are not fully concordant, both are influenced by landscape permeability, and show a similar east-west gradient. Our results suggest that this permeability was a stronger factor limiting gene flow among human populations in the Caucasus than ethnic or linguistic boundaries.
Tarkhnishvili, David; Gavashelishvili, Alexander; Murtskhvaladze, Marine; and Latsuzbaia, Ardashel, "Landscape Complexity in the Caucasus impedes Genetic Assimilation of Human Populations More Effectively than Language or Ethnicity" (2017). Human Biology Open Access Pre-Prints. 105.