Screening Of Important Candidate Gene SNPs Related To Yunshang Black Goat Litter Size

Goats are important agricultural economic animals.Increasing the number of litters per litter is an important way to improve goat production performance.Due to the long generation interval of goats,it is difficult to quickly increase the litter size by using traditional breeding methods.The molecular marker-assisted selection has the advantages of high accuracy,strong operability,saving breeding costs,etc.,and can improve goat lambing traits more efficiently and quickly.Therefore,the use of molecular marker-assisted selection technology is conducive to the selection of high fertility goats,speeding up the breeding process,and providing more convenience for goat selection and breeding.In this study,15 candidate genes AMH,AHMR2,ADCY1,CYM,DNMT3B,KHDRBS2,EGR4,KDM4C,KDM6A,ESR1,TENM1,THEM4,IGF1,RBP4,ALAS1and their corresponding 36 SNPs locus associated with goat litter size were obtained based on GWAS data.They were typed using Sequenom Mass ARRAY^?SNP typing technology and correlated with phenotypic data of litter size of 544 Yunshang black goats.Four SNPs locus were finally screened and significantly correlated（P<0.05）with litter size of Yunshang black goat:RBP4 g.36491960G>C,IGF1 g.64943050T>C,KDM4C g.37764228T>A and ALAS1 g.48791372C>A.The results show that these 4SNPs can be used as potential molecular markers for the selection of litter size of Yunshang black goats.In order to further study the mechanism of the four SNPs locus affecting goat litter size,we selected three SNPs located in the upstream 5’regulatory region of the gene conducted in-depth research and detected the expression of candidate genes mRNA in ovarian tissues in mutant and wild-type individuals through fluorescence quantitative PCR technology.The results showed that the three SNPs located in the upstream5’regulatory region all affected gene mRNA expression.Among them,RBP4 CC（mutant,high-yield group）individuals had significantly higher RBP4 expression than GG（wild-type,low-yield group）individuals;IGF1 expression of IGF1 CC type（mutant,high-yield group）individuals was significantly higher than that of TT type（wild type,low-yield group）individuals;ALAS1 AA type（mutant,high-yield group）individuals ALAS1 gene expression was significantly higher than that of CC type（wild type,low-yield group）individuals（P<0.05）.The results showed that SNPs can lead to changes in gene expression,and it is hypothesized that changes in litter size in goats may be regulated by the expression of candidate genes.In summary,this study performed an association analysis of 15 candidate genes and corresponding SNPs with Yunshang black goat litter size traits,and found that 4SNPs were significantly correlated with the goat’s litter size,and three SNPs were verified.The results of this study can provide a theoretical reference for the breeding of high fertility individuals of this breed of goats,and can provide certain scientific support for the preparation of rapid detection kits for goat multi-lamb genes.