| The polymorphisms of seventeen sites which were intron 1,4,10,11,18,19,25, and 3′UTR of STAT1gene(GeneID:510814)and exon7-12, intron 14 of STAT5A gene(GeneID: AJ237937)were detected in 199 Chinese Holstein cattle with PCR-SSCP , and the association between the polymorphisms and milk production traits of three birth orders were analyzed. The aim was to choose perfect markers which can provide theoretical base for breeding in dairy cattle. The results were as follows:Only three sites existed polymorphism in STAT1 gene and two sites in STAT5A gene, which were intron11 (P1and P2), 3′UTR of STAT1 gene and intron9, 14 of STAT5A gene. The analysis of association between different genotypes and milk traits were showed as follows:1. The association between polymorphism of intron11 (P1) of STAT1 gene and milk production traitsPrimer designed by primer5.0 were used to amplify the DNA of ChineseHolstein cattle, the length of product was 369 bp. Three genotypes AA,AB andBB were identified after PCR-SSCP, the frequency of each genotype was: 0.442,0.462,0.096.The sequencing results showed that the mutation was chage of G→A in position 28739.the analysis between different genotypes and milk production traits showed that : cows with genotype BB had significantly higher protein percent (P%) in the first and second birth orders than that of genotype AA and AB(P<0.05); there were no significant differences among three genotypes on 305 days milk yield, and fat percent (F%) of all birth orders, while the tendency of BB>AB>AA was showed.2. The association between polymorphism of intron11 (P2) of STAT1 gene and milk production traitsThe product amplified by primer P2 was analyzed by PCR-SSCP. There were three genotypes: CC, CD and DD, the frequency of each genotype was: 0.331, 0.196, 0.473. The sequencing results showed that three genotypes were caused by the mutation of G→C in position 28873. the analysis between different genotypes and milk production traits showed that: cows with genotype DD had significantly higher milk yield in the third birth order than that of genotype CC (P<0.05), cows with genotype DD had significantly higher protein percent (P%) in the second birth order than that of genotype CC,CD (P<0.05), there were no significant differences among three genotypes on fat percent (F%) of all birth orders(P>0.05). 3. The association between polymorphism of 3′UTR of STAT1 gene and milk production traitsThree primers were designed to amplify different segments in 3′UTR, while only one segment was found polymorphism. There were three genotypes: TT, CT and CC, the frequency of each genotype was: 0.437, 0.116, 0.447. The sequencing results showed that the mutation was C→T in position 141930. the analysis between different genotypes and milk production traits showed that: Cows with genotype CC or TT had significantly higher 305 days milk yield in the first and second birth orders; and cows with genotype CC had significantly higher protein percent (P%) than genotype TT in the first and third birth orders; there were no significant differences among three genotypes on fat percent (F%).4. The association between polymorphism of intron9 of STAT5A gene and milk production traitsExon 10 was amplified by one primer, the segment was analyzed by PCR-SSCP, three genotypes GG, AA and GA were found, and the frequency of each genotype was: 0.112, 0.138, and 0.75. The sequencing results showed that the mutation was in intron 9, which were G→A in position 9501. the analysis between different genotypes and milk production traits showed that : Cows with genotype AA had significantly higher 305 days milk yield than genotype GA and GG in the third birth orders(P<0.01), Cows with genotype GG had significantly higher protein percent (P%) than genotype AA and GA in the second and third birth orders(P<0.05), Cows with genotype GG and GA had significantly higher fat percent (F%) than genotype AA in the first and third birth orders(P<0.05).We could conclude that the effect of STAT1 gene and STAT5A gene on milk trait was obviously, so these two genes could be used as candidate genes for MAS of Chinese Holstein cattle.
|
PDF Full Text Request