Genetic distances between Russians from different country regions and other populations of Russia

The major histocompatibility antigen (HLA) complex is among the most polymorphic genetic systems in humans. The distribution of HLA alleles and haplotypes differs within ethnic groups and geographical regions. Russian populations evolving in different regions of Russia may have distinct immunogenetic characteristics due to the influence of internal and external factors (vast territories, multinational population, interethnic contacts). The aim of this study was to evaluate the genetic distances between Russians from different regions of Russia, and other populations. The results of this study show that the Russians living in St. Petersburg, Nizhny Novgorod and Rostov-on-Don had a similar distribution of HLA allele groups. The pan-European HLA haplotypes A*01-B*08-C*07-DRB1*03-DQB1*02 and A*03-B*07-C*07-DRB1*15-DQB1*06 were most common in Russians from all regions. When comparing 10 most common HLA haplotypes, nine of them were similar for the residents of St. Petersburg and Nizhny Novgorod. In addition, we have registered the following haplotypes: A*02-B*13-C*06-DRB1*07-DQB1*02 , A*03-B*35-C*04-DRB1*01-DQB1*05 , A*02-B*07-C*07DRB1*15-DQB1*06 , A*02-B*18-C*07-DRB1*11-DQB1*03 , A*25-B*18-C*12-DRB1*15-DQB1*06 , A*02B*41-C*17-DRB1*13-DQB1*03 , A*30-B*13-C*06-DRB1*07-DQB1*02 . The A*02-B*15-C*03-DRB1*04DQB1*03 haplotype was one of the most common among Russians of St. Petersburg, but its frequency was less in Russians from Nizhny Novgorod (0.0119 vs. 0.0034, p = 0.03) and it was not found among Russians of Rostov-on-Don. The residents of Rostov-on-Don had the more significant differences of HLA haplotype profile. In particular, the following HLA haplotypes were among the most common in Russians living in Rostov-on-Don: A*23-B*44-C*04-DRB1*07-DQB1*02 , A*02-B*57-C*06-DRB1*07-DQB1*03 , A*24-B*35C*04-DRB1*11-DQB1*03 , A*01-B*52-C*12-DRB1*15-DQB1*06 , A*11-B*35-C*04-DRB1*01-DQB1*05 , A*02-B*27-C*02-DRB1*01-DQB1*05 , A*02-B*44-C*02-DRB1*16-DQB1*05 . Two of these haplotypes ( A*24B*35-C*04-DRB1*11-DQB1*03 and A*02-B*44-C*02-DRB1*16-DQB1*05 ) were not detected in Russians of Nizhny Novgorod, the frequency of other haplotypes was < 0.01. Frequency of these haplotypes in Russians of St. Petersburg was also less than 0.01. The haplotype A*23-B*44-C*04-DRB1*07-DQB1*02 was less common in Russians of St. Petersburg (0.0246 vs. 0.0062, p = 0.01). An analysis of genetic distances between populations showed that Russians of Nizhny Novgorod, as well as Russian residents of Moscow and Belarus were the closest to Russians living in St. Petersburg. The genetic distance between Russians living in St. Petersburg and the residents of Rostov-on-Don and Chelyabinsk Region is a bit greater. Comparison of genetic distances between the various Slavic populations showed that the Eastern (Belarusians, Russians) and Western (Poles, Slovaks, Czechs) Slavs are closest to each other. The Southern Slavic folks (Serbs, Croats, Macedonians) are more genetically remote. The results of present research can be used to study the processes of ethnogenesis, searching for associations between HLA and diseases, and also being applied in practical activities of hematopoietic stem cell donor registries.