| Abstract [eng] |
The main purpose of this master thesis is to analyze signatures of positive natural selection of two main ethnolinguistic groups, Žemaičiai and Aukštaičiai, from genome-wide SNP genotyping data. The main question is whether natural selection is acting equally on genomic groups under study. Identifying positive natural selection in the human population provides an opportunity to understand the phenotypes of modern humans and their ability to adapt to changing environmental conditions. The genome areas affected by the natural selection identified in this research fill the knowledge gaps in this area and help determine their effect on the phenotype and identify adaptive alleles. Genome-wide high-density SNP genotype data in 425 individuals from six geographical regions in Lithuania were used to find signatures of natural positive selection in the Lithuanian population and check for population structure. The results show that Lithuania is a homogeneous population and that all ethnolinguistic groups form one cluster. Different genomic regions under natural positive selection were detected in Aukštaičiai and Žemaičiai ethnolinguistic groups. Among the top signatures of positive selection detected in the ethnolinguistic populations, we identified several candidate genes related to diet (SMKR1, SEMA6D and MRA), body mass index BMI (NRF1, LRRC36, ZDHHC1, HSD11B2, PNLIPRP3, PNLIP, DNAH7, HLA-DMA, STAM2, STK17B, DNAJB8). The results support the theory that positive natural selection can occur even at the micro-geographical levels. Dependency on an ethnolinguistic region might be considered an important factor for the genetic data analysis. |
