Single Nucleotide Polymorphism Of MyoG,GH And CKM Gene In Tibetan Sheep Populations And Its Association With Growth Traits

PCR-SSCP technology and DNA sequencing was applied to analyze the polymorphisms of MyoG,GH and CKM gene in 632 Tibetan sheep, including Guinan Black Tibetan sheep(GN), Qilian gaoyuan Tibetan sheep(QL) and Henan Oula Tibetan sheep(HN). This research was to investigate polymorphisms of of MyoG,GH and CKM gene and evaluate their effect on growth traits in Tibetan sheep. The aim was to choose perfect markers which can provide theoretical base for breeding in Tibetan sheep.There are 2 mutations were detected in MyoG gene which located at g.109A>C(in exon 1), g.1403A>C(in intron1)separately, 3 mutations were detected in GH gene which located at g.498G>C(in exon 2), g.616G>A(in intron2) and g.624G>A(in intron2) separately, 2 mutations were detected in CKM gene which located at g.8068C>G(in intron6) and g.8322A>G(in intron7) separately. The analysis of association between different genotypes and growth traits were showed as follows: 1. The association between polymorphism of MyoG gene and growth traits in Tibetan sheepThere were three genotypes CC, CA and AA detected at g.109A>C locus of MyoG gene in Tibetan sheep populations, this mutation leads to a missense mutation from Glu(GAG) to Ala(GCG) in 37 amino acid. In this locus PIC(polymorphism information content) is belonged to moderate polymorphisms. Statistical analysis indicated that in Henan Oula Tibetan sheep population, animals with the CC genotype have higher mean values for body weight, body height and body length than those with the AA genotype(P <0.05); in Qilian Gaoyuan Tibetan sheep population, animals with the CC genotype have higher mean values for body weight than those with the AA genotype(P <0.05); in Guinan Black Tibetan sheep population, animals with the CA and AA genotype have higher mean values for body length than those with the CC genotype(P <0.05).There were three genotypes AA, AC and CC detected at g.1403A>C locus of MyoG gene in Tibetan sheep populations. Statistical analysis indicated that in Henan Oula Tibetan sheep population, animals with the AA genotype have higher mean values for body weight and body height than those with the CC genotype(P <0.05); in Qilian Gaoyuan Tibetan sheep population, animals with the AA genotype have higher mean values for body weight and body length than those with the CC genotype(P <0.05). 2. The association between polymorphism of GH gene and growth traitsThere were three genotypes GG, GC and CC detected at g.498G>C locus of GH gene, this mutation leads to a samesense mutation from Pro to Pro in 87 amino acid. GG was the preferable genotype and G was the advantage allele. In this locus PIC is belonged to moderate polymorphisms. The χ2-test showed that 3 populations at g.498G>C locus were all at at Hardy-Weinberg disequilibrium. Statistical analysis indicated that in HN population, animals with the GG genotype have higher mean values for body weight and body length than those with the CC genotype(P <0.05); in QL population, animals with the GG genotype have higher mean values for body weight, body length, body height and chest circumference than those with the CC genotype(P <0.05), in GN population, animals with the GG genotype have higher mean values for body weight and body length than those with the CC genotype(P <0.05). Three genotypes GG, GAand AA were identified in g.616G>A locus of GH gene. Locus PIC is belonged to moderate polymorphisms. Statistical analysis indicated that in HN population, animals with the AA genotype have higher mean values for body weight, body length, body height and chest circumference than those with the GG genotype(P <0.05); in QL population, animals with the AA genotype have higher mean values for body length than those with the GG genotype(P <0.05).GG,GA and AA genotype was detected at g.624G>A locus of GH gene, GG and C were the preferable genotype and advantage allele, separately. In this locus PIC is belonged to moderate polymorphisms. This mutation site was no significant influence on growth traits. 3. The association between polymorphism of CKM gene and growth traitsTwo SNPs(g.8068C>G and g.8322A>G) were identified in intron 6 and intron 7 of CKM gene. 3 genotype were identified at each locus and locus PIC is belonged to moderate polymorphisms. At g.8068C>G locus the individuals with CC genotype had higher body weight and body height than those with GG genotype in HN population, the individuals with CC genotype had higher body weight, body height and chest circumference than those with GG genotype in QL population, the individuals with CC genotype had higher body weight and body length than those with GG genotype in GN population. At g.8322A>G locus, there was no significant influence on growth traits in 3 population.