Rsb 분석법을 활용한 칡소의 선발신호 탐색 연구

Korean cattle (Hanwoo) are categorized into three types of breeds according to their color, namely brown, brindle and black. Among the three breeds, Chikso (brindle Hanwoo) have been maintained at very low population sizes in South Korea and have unique brindle patterns. In this study, Rsb method was applied to identify genomic regions of artificial selection for traits in Chikso. To identify traces driven by the artificial selection process, we scanned the genome of set of brown and brindle Hanwoo using 50K SNP Chip. As a result, we identified 37 highly homozygous regions that seem to be very strong and/or recent selections in Chikso compared to the brown Hanwoo from Rsb analysis. Among these regions, BTA11:100-102.5 Mb is the strongest selection signal having 17 significant SNPs. To go further in the interpretation of the observed signatures of selection, we subsequently performed functional enrichment analysis using 207 candidate genes. As a result, candidate genes have enriched GO or KEGG pathway terms such as unsaturated fatty acids metabolic process(e.g., PTGES2 and ANGPTL2) or immune system (e.g., Fc gamma R-mediated phagocytosis). They have important roles in the domestication process of livestock. We also detected the common signature (BTA1:2 – 2.5 Mb) of selection between Chikso and brown Hanwoo. SYNJ1 gene residing within the region is associated with the horn development as candidate gene. This observation suggests that Chikso and brown Hanwoo have a common genetic characteristic as Hanwoo breed during domestication. However, only one selection signature means that they seem to be processed in a different way during domestication. Chikso may has a founder effect as very low population from the results of heterozygosity and fixed SNPs calculation. From the results, this analysis also led to the identification of candidate genes as having a strong signal of artificial selection in Chikso.