Polymorphism Of Holstein Cows Mastitis Gene And Its Association With Somatic Cell Score

265 Holstein cow blood samples were applied to analyze the single nucleotide polymorphisms of OSTF1,α1-AT,HNRPU and ITGB2 gene. The correlation between SNPs and somatic cell scores (SCS) was analyzed using least-squares analysis.PCR-SSCP and DNA sequencing technologies were used to detect the SNPs of OSTF1 gene; PCR-SSCP, DNA sequencing, PCR-RFLP and CRS-PCR technologies were used to detect the SNPs ofα1-AT gene; PCR-SSCP and DNA sequencing technologies were used to detect the SNPs of HNRPU gene; DNA sequencing and PCR-RFLP technologies were used to detect the SNPs of ITGB2 gene. The results as follows:1. Two polymorphic sites at A45416G and C45436T were found in which A45416G mutation of OSTF1 gene resulted in amino acid change of Methionineâ†'valine.AA(0.515),AB(0.366) ,BB(0.075) , AC(0.035) and CC(0.009)genotypes were found in Holstein cows. Least squares mean of SCS for BB was significantly lower than that for AB, AC or CC (P<0.05), and the difference of the least squares means for SCS among AA,AB and AC was not significant (P>0.05). AA was the most unfavorable genotype, and BB was the most favorable genotype for mastitis resistance. The results implied that B allele of OSTF1 gene can improve mastitis resistance in dairy cattle.2. Two polymorphic sites at G5503A and G5746C ofα1-AT gene were found. AA(0.3633), AB(0.4644) and BB(0.1723) genotypes were detected at G5503A site and CC(0.3483), CD(0.4906) and DD(0.1611) were found at G5746C in Holstein cows. AACC(0.2697), AACD(0.0899), AADD(0.0075), ABCC(0.0749), ABCD(0.3408), ABDD(0.0412), BBCC(0.0037), BBCD(0.0599) and BBDD(0.1124) genotypes combinations were found. Least squares mean of SCS for BB was significantly lower than that for AA and AB (P<0.01) and AB was significantly lower than that for AA(P<0.05) and CC,CD and DD was not significant (P>0.05). AA was the most unfavorable genotype, and BB was the most favorable genotype. Least squares mean of SCS for BBDD genotype combination was significantly lower than AACC and AACD. AACC and AACD were unfavorable genotype combinations, and BBDD was a favorable genotype combination. The results implied that B allele gene and BBDD genotype combination ofα1-AT can improve mastitis resistance in dairy cattle.3. Three genotypes AA, AB and BB were detected at C7277T of HNRPU gene and the frequencies of three genotypes were 0.3507,0.4408 and 0.2085. Least squares mean of SCS for BB was significantly lower than that for AA and AB (P<0.01) and AB was significantly lower than that for AA(P<0.05). AA was the most unfavorable genotype, and BB was the most favorable genotype for mastitis resistance. The results implied that B allele of HNRPU gene can improve mastitis resistance in dairy cattle.4. Two polymorphic sites at T18587C and G28301A of ITGB2 gene were found. AA(0.3517), AB(0.4788) and BB(0.1695) genotypes were detected at T18587C site and CC(0.5678), CD(0.3771) and DD(0.0551) were found at G28301A in Holstein cows. AACC(0.2881),AACD(0.0636),ABCC(0.2585),ABCD(0.1991),ABDD(0.0212),BBCC(0.0212),BBCD(0.1144) and BBDD(0.0339) genotype combinations were found. The difference of the least squares means for SCS among AA,AB and AC was not significant (P>0.05) and CC,CD and DD were significant (P<0.05). CC was the most unfavorable genotype, and DD was the most favorable genotype for mastitis resistance. The difference of the least squares means for SCS among genotype combinations was not significant (P>0.05). The results implied that D allele of ITGB2 gene can improve mastitis resistance in dairy cattle.In summary, B allele of OSTF1 gene, B allele and BBDD genotype combination ofα1-AT gene, B allele of HNRPU gene and D allele of ITGB2 gene are potential DNA markers for improving mastitis resistance in dairy cattle.