SNP-BASED ASSESSMENT OF POPULATION STRUCTURE AND ADAPTIVE VARIATION IN CLIMATE-RESPONSIVE SPECIES

Abstract

The proposed research will evaluate the population composition of climate-sensitive species using SNP high-resolution and gauge adaptive genetic variations in relation to environmental gradients. Genome-wide SNP data has been created through complex genotypeing methods (restriction site-associated DNA sequencing (RAD-seq) or whole-genome sequencing (WGS)). Population structure was compared by principal component analysis (PCA) and the model based clustering techniques such as the STRUCTURE and ADMIXTURE, whereas genetic variation and differentiation were measured as observed heterozygosity (Ho), expected heterozygosity (He) and a fixation index (Fst). Moreover, SNP loci that were significantly correlated with the climatic variables were identified by environmental association analysis, which allowed identification of the adaptive signatures. Findings showed that there was evident genetic clustering of the groups of people showing different population structure due to geographic and environmental influences and high degree of genetic differentiation as indicated by moderate to high Fst values. The type of SNP loci that was identified to be closely associated with the important climatic factors were found to be a few in number and this fact indicates that it is necessary to have a number of SNP loci in order to bring about local adaption and environmental responsiveness. Altogether, the results are excellent evidence of genetic adaptation under the impact of climate, which proves that SNP-based methods prove to be extremely useful in solving the population structure and identifying adaptive variation. These findings can be used in conservation genomics, biodiversity management, and in breeding strategies to be resistant to climate changes.