The role of Caucasian, Iranian and Steppe populations in shaping the diversity of autosomal gene pool of the Eastern Caucasus

Balanovska EV1,2, Gorin IO1, Petrushenko VS1, Ponomarev GYu1, Belov RO1, Pocheshkhova EA1,3, Salaev VA1, Iskandarov NA1, Pylev VYu1,2
About authors

1 Bochkov Research Centre of Medical Genetics, Moscow, Russia

2 Biobank of North Eurasia, Moscow, Russia

3 Kuban State Medical University, Krasnodar, Russia

Correspondence should be addressed: Vladimir Yu. Pylev
Moskvorechye, 1, 115522, Moscow, Russia; ur.xednay@tsurteerf

About paper

Funding: the study was supported by the RSF grant № 21-74-00156 (bioinformatics analysis of gene pools of the Eastern Caucasus and Transcaucasia), State Assignment of the Ministry of Science and Higher Education of the Russian Federation for the Research Centre of Medical Genetics (cartographic analysis, data interpretation), Biobank of North Eurasia (expedition survey).

Acknowledgements: the authors would like to thank all members of the expedition survey (sample donors) and the autonomous non-profit organization “Biobank of North Eurasia” for access to DNA collections and the genotyping results.

Author contribution: Balanovska EV — management, design, manuscript writing and expedition survey of the Dagestani peoples; Gorin IO, Petrushenko VS — bioinformatics analysis; Ponomarev GYu — work with DNA collections, cartographic analysis; Belov RO — work with DNA collections, manuscript formatting; Pocheshkhova EA — expedition survey of the Dagestani peoples; Salaev VA — organization and conducting the expedition survey of the Talysh living in Azerbaijan; Iskandarov NA — organization and conducting the expedition survey of the Azerbaijanis living in Azerbaijan; Pylev VYu — organization of genotyping, statistical analysis.

Compliance with ethical standards: the study was approved by the Ethics Commitee of the Bochkov Research Centre of Medical Genetics (protocol № 1 of 29 June 2020).

Received: 2023-04-26 Accepted: 2023-05-13 Published online: 2023-05-29

Eastern Caucasus is home to more than 30 peoples speaking Caucasian, Iranian and Turkic languages. Fusion of multiple migration flows together with the complex population structure of the Eastern Caucasus make it more difficult to analyze its gene pool: this is the most poorly studied one among all regions of the Caucasus. The study is aimed to identify the main patterns of the autosomal gene pool variation in this region. A total of 356 genomes of 29 ethnic groups were studied using the large panels of SNP markers: 243 genomes of 22 peoples of the Eastern Caucasus and 113 genomes of 7 peoples living in adjacent regions. The bioinformatics analysis involved the use of the ADMIXTURE ancestral component method and the gene pool variability principal component analysis (РСА). The hypothesis of three genetic strata, the interaction of which forms the structure of gene pool of the Eastern Caucasus, was put forward. The “Dagestan” stratum carries information about the gene pool of the ancient autochthonous population of the Eastern Caucasus. The “Iranian” stratum represents the legacy of ancient and middle-aged migrations surges of the Iranian-speaking population: it constitutes three quarters of the gene pool of modern Azerbaijan and about one third of the Dagestan peoples' gene pool. The “Steppe” stratum represents a negligible influence of the Eurasian steppe. Interaction of three genetic strata is only indirectly related to the peoples' linguistic affiliation, however, the association with linguistics is more obvious in the Caucasian-speaking peoples. Four genetically distinct groups of indigenous population of the Eastern Caucasus have been identified, the combination of which should be included in the characteristics of its autosomal gene pool: 1) Dargins, Laks; 2) Avars, Lezghins, Tabasarans, Aghuls, Rutul people, Tsakhur people; 3) Kumyks, Tat people and Azerbaijanis living in Dagestan; 4) Azerbaijanis and Talysh living in Azerbaijan. The directions of further research have been defined.

Keywords: gene pool, gene geography, population, population genetics, autosomal SNP markers, Eastern Caucasus