Associations Ot SNP In Candidate Genes With The Horn Trail And CART Gene Polymorphism Analysis In Yaks

In this research, high-resolution melting (HRM) was used to study the polymorphism of horn traitcandidate gene and Cocaine-and Amphetamine-Regulated Transcript gene (CART) in yak.Horn trait candidate gene experiment: Cattle and sheep usually have horns, however polledindividuals also exist. It is people usually think that the hornless trait is controlled by the polled geneand which is located on the chromosome1in some researches, however the hornless trait geneticmechanism has not been clarified. Based on cattle polled candidate gene information of cattle, wedetected the SNP of this region, and screened the candidate polled gene of yak with association analysis.extracted the Genomic DNA was extracted from51horned and50polled Datong yak blood samples.andPrimers were designed to detect polymorphic in polled gene candidate region which contained12genen the horned/polled yak, The effect of partial SNPs on gene function was analysed by bioinformaticsmethod..61SNPs were found in this test,9SNPs of them were significant associationwith hornlesstraits (2in3’UTR,5in intron,2in intergenic sequences) by Fisher’s test.2SNPs sites led to changeRNA secondary structure, which might impact the individual SYNJ1gene expression of the horned andthe polled. Haplotype analysis showed that the9SNPs were tightly linkage. The yak hornless candidategenes might be located between the9SNPs (147KB), in which included3known gene namedC1H21orf62, GCFC1and SYNJ1, respectively.CART experiment: The purpose of this study were to clone Cocaine-and Amphetamine-RegulatedTranscript gene (CART),obtain the full length of the gene, analyze the genetic variation characteristicsand find several SNPs in different yak breeds. The influence of SNP on CART gene expression was alsopredicted by bioinformatics analysis, which might provided some basic information for functionresearch of CART in future. The blood samples of243Datong yak,208Tianzhu yak,208Gannan yak,53Pali yak were used to isolate the genomic DNA and the full length of CART gene was cloned andsequenced. Gene variants and the distribution of polymorphism in different breeds were detected byHRM, and g the potential impact on CART gene expression caused by SNPs was predicted bybioinformatics analysis. In this study, the results showed that five novel SNPs located in CART genewere identified, which were located in upstream, intron,3’-UTR and downstream of CART gene.2tests showed that all the other loci in all experimental populations were all in the status ofHardy-Weinberg equilibrium (P＞0.05), except the C-221G in Datong population and C1816T inGannan population. Population genetics analysis results showed that C168T, C1816T and C2240A lociwere at intermediate polymorphic status, C-221G and G1791A loci were at low polymorphic status. Thehaplotype C is an advantage type haplotype. Bioinformatics analysis showed that different alleles ofG1791A and C1816T might change the RNA secondary structure, which should influence expression ofCART gene. In this study,5novel polymorphism sites were found in CART gene of yak, which showedhigh or moderate polimorphism. The nucleotide variation of G1791A and C1816T loci reduced RNAstability that might produce negative influence on CART gene expression.