Genetic Diversity Of 10 Coat Color Related Candidate Genes In Four Yunnan Goat Breeds

The domestic goat(Capra hircus),as one of the earliest humanized animals,not only brings economic value to humans,but also plays an important role in the entire human history process.Therefore,its evolution and diffusion process has been the focus of geneticists and archaeologists.Over time,domestic goats in Yunnan have cultivated local breeds with different coat colors(such as yellow,black and white)through artificial selection.The coat color is one of the characteristics that distinguish animal breeds.However,due to there are relatively few studies on goat coat color,and the genetic mechanism of goat coat color is not thoroughly studied.In this study,10 candidate genes that may be related to goat coat color were selected to study to verify whether it is related to goat coat color.Four Yunnan local goat breeds were selected for this study,including Luoping Yellow Goat,Weixin White Goat,Shizong Black Goat and Yunling Black Goat.Each sample was randomly selected from 30 samples.First,the PCR amplification products were directly sequenced to obtain partial CDS sequences of the 10 candidate genes related to coat color of the four varieties ADAMTS20,EXOC2,HTT,IRF4,KDR,KITLG,OSTM1,PDGFRA,RALY,TIMP3;then the sequence was analyzed for genetic diversity,phylogenetic geographic structure,population history,selection pressure,and distribution frequency of polymorphic sites(SNPs);finally,from a statistical point of view,whether the 10 candidate genes are related to the expression of goat coat color.The results showed that:1.The genetic diversity of the four Yunnan local goat breeds is relatively rich,of which the white goat(Weixin white goat)has the highest genetic diversity and the yellow goat(Luoping yellow goat)has the lowest,two kinds of black goats(Yunling black goats and Shizong black goats)followed;there is no significant genetic differentiation among the four populations,frequent genetic exchanges between the populations,and the four goat populations have recently experienced population expansion.2.According to the frequency distribution of SNPs loci,8 out of 10 candidate genes related to coat color showed significant or extremely significant difference sites,a total of 19,respectively: g.C469 T and g.C558 G of ADAMTS20 gene,g.A205 G of EXOC2 gene,g.C272 T,g.T778 C and g.C894 T of HTT gene,g.C329 A and g.C910 T of IRF4 gene,g.C310 T,g.A509 G,g.C659 T,g.A661 G and g.C939 T of KDR gene,g.G283 A of KITLG gene,g.C324 T and g.T814 A of PDGFRA gene,g.C68 T,g.G94 T and g.C864 T of TIMP3 gene;four of these genes have non-synonymous mutation sites: ADAMTS20(g.C558G),EXOC2(g.A205G),HTT(g.T778C)and KDR(g.A509G),this suggests that these eight genes may be related to goat coat color.The remaining two genes OSTM1 and RALY have no significant differences in the four goat breeds,and this suggests that these two genes may have nothing to do with the goat’s coat color.The 10 candidate genes were not under positive selection pressure on the four Yunnan goat breeds.This study provided relevant evidence for revealing the genetic diversity of Yunnan domestic goats,screening of candidate genes related to coat color and protecting local breeds,which laid the foundation for further research on Yunnan domestic goat.