| 54 bulls and 30 castrated ones of Xingjiang brown cattle,15 Holstein bulls were chosen to measure the growth traits(body size and daily gain).The genetic polymorphism of MYF5,PPARy and AGP AT genes,as well as their association with growth traits were analyzed in this study.The results showed as follows:(1)By comparing the body size of the three groups,it was found that the chest circumference and chest width of Holstein bulls were smaller than Xinjiang Brown bulls,while the cross height was higher than Xinjiang brown bulls.The castrated ones of Xingjiang brown cattle were lower than the Xinjiang brown bull in body sizes.In feeding,the daily gain curve of the three groups was similar in 10-14 month old,and after 14 months old,the daily gain of Holstein bulls increased,while declined in castrated and uncastrated Xinjiang brown bull.Compared with the body size and chest length,chest width had a significant influence on body weight and daily gain.(2)The sequencing and RFLP showed that there were 10 polymorphic loci at PPAR γ、MYF5 and AGPAT5.AB genotype of SNP1(PPAR gamma gene G74T mutation in exon 7)was significantly correlated to chest circumference,body weight,and daily gain;AB genotype of SNP2(PPAR gamma gene intron 2 G133C,C170T mutation)was significantly related to body length,chest circumference,body weight and daily gain.The AB genotype of SNP3(T236C mutation of exon 1 of MYF5 gene)was significantly related to body length and chest circumference.The AA genotype of SNP4(A633G mutation in intron 1 of MYF5)was significantly related to breast width.The AB and AA genotypes of SNP5(G501C,G515T and G550T mutations in intron 3 of AGPAT5)were significantly related to body length,chest circumference,chest weight,and daily gain.The AA and AB genotypes of SNP6(G72A and A97G mutations in exon 7 of AGPAT5 gene)were significantly related to chest circumference,chest width,body weight and daily gain.Analysis of polymorphisms and Hardy-Weinberg of 6 SNPs revealed that only SNP2 and SNP5 were reasonable.The body length,chest circumference,weight and daily gain of AB genotype in SNP2 loci were significantly higher than those of AA and BB genotype individuals(P<0.05).The body length,chest circumference,chest width,body weight and daily gain of individuals with AB and AA genotypes in SNP5 loci were significantly higher than those in BB genotype individuals(P<0.05).(3)Haplotype analysis showed that GCC haplotype is dominant haplotype of PPARγ-exon7(74)-intron2(133,170)gene,same as the CG haplotype of MYF5-exon1(236)-intron1(633)gene and the GTGGGhaplotype of AGPAT5-exon7(72,97)-intron3(501,515,550)gene.These results will provide basis for the subsequent breeding and genome selection of Xinjiang brown cattle. |
