Polymorphisms Of SLA-DRB And POU1F1Genes And Its Associations With Several Growth Traits In Artificial Populations Of Tibetan Pigs

In this study, the single nucleotide polymorphisms (SNPs) of SLA-DRB gene were detected in108artificial populations of Tibetan pigs from Pujiang county, Sichuan province, and POU1F1gene in239Tibetan pigs from eight districts using sequence based genotyping (SBT-PCR) methods, and the genetic structures of the two genes in populations were analyzed. Then, the association analysis between SNPs and growth traits of cultivated Tibetan pigs was calculated to assess the efficiency of SLA-DRB and POU1F1genes for marker-assisted selection (MAS).The differential analysis demonstrated significant differences of growth traits (month2to month9) between genders in the artificial Tibetan pig population. Comparing with boars, sows had significant (P<0.05) effects on heart girth (month4to month7), abdominal girth (month4to month9), chest width (month5to month8), chest depth (month6and month7), hip width (month5to month9), body weight (month5to month7, buttock length (month6) and head depth (month6). Besides, range from month2to9, sows showed greater than boars in the traits of chest depth, chest width, heart girth, abdominal girth, buttock length, hip width and body weight.14SNPs were detected in SLA-DRB gene (the3th intron,4th exon and4th intron) in artificial populations of Pujiang County, among which ten SNPs (g.11369OG, g.11387A>G, g.11470A>G, g.11478>T, g.11532A>G, g.11829A>G, g.11838C>T, g.11944C>G, g.11945A>G and g.11997C>T) were medium polymorphic (0.25<PIC<0.5) and the rest SNPs (g.11440C>T, g.11468C>T, g.11708C>T and g.11911T>G) showed lower polymorphism (PIC<0.25). Chi-square compatibility test showed that except the site g.11468, other13SNP sites were not in Hardy-Weinberg Equilibrium (P<0.05). And the association analysis between growth and every single site revealed significant relevance between SLA-DRB gene and Tibetan boars of Month2to4. However, dissimilar relationship were showed between SLA-DRB gene and Tibetan sows, which implied that the gender difference had to be considered while using SNPs of SLA-DRB gene for early stage selection in this artificial Tibetan pig population.We also genotyped the polymorphism of4th intron of POU1F1gene among239Tibetan pigs from eight districts. As a result,7SNPs (g.13952A>G, g.14009A>G, g.14192T>C, g.14384G>C, g.14387A>G, g.14392C>G, g.14464T>A) were detected. Respectively, all of the SNPs had been detected among populations from Derong county and Dege county. However, the SNPs at site g.14009(A>G) and site g.14392(C>G) had not been detected among populations from Daocheng county, and1SNP (g.14392C>G) had not been detected in pig populations of Batang county and Danba county. The missing SNP of Tibetan pigs from Ganzi county was g.14387A>G, which was the unique SNP detected within the population of Xiangcheng county. The gene of the Tibetan pigs from Pujiang county have been detected4SNPs (g.13952A>G, g.14192T>C, g.14384G>C and g.14464T>A).4SNPs (g.13952A>G, g.14192T>C, g.14384G>C, and g.14464T>A) were detected in Tibetan pigs from Pujiang county, of which site g.14192and site g.14384showed completely genetic linkage. Association analysis between growth traits and each SNP demonstrated that individuals with TT genotype at g.14464locus performed relatively poor growth, while just femina with AA and AG genotype at g.13952locus appeared to the analogous phenotype. Therefore, the disadvantage effect of T allele at g.14464locus can be suggested as a marker assisted selection reference in Tibetan pig. The correlation analysis between growth traits and haplotype combination illustrated that individuals with H1H1haplotype presented lowest growth rate, suggesting that more attention should be paid to H1H1haplotype pigs during the further miniaturization selection of Tibetan pigs.