| Combining biological software and bioinformatics, the characteristics of sirtuins gene families of DNA and protein were analyzed. The tissue expression of SIRT1 and SIRT2 were analyzed by Real-time-PCR and bioinformatics, while the polymorphism of SIRT1-7 genes were analyzed by PCR-RFLP and DNA sequencing techniques. The frequency, equability, total heritability and relevance of body measurement traits of 27 SNPs were analyzed by Bio-statistics. In order to produce scientific proof for marker-assisted selection of growth and meat quality traits of Qinchuan beef cattle and build scientific basis for high-yield breeding skills of new breed, some of the effective function genes and molecular markers were selected in our study research. The main results of our study are as followed:Via PCR-RFLP technology conducted in 453 individuals of Qinchuan beef cattle, single nucleotide polymorphisms(g.25764 G > A, g.25846 A > G, and g.25868 T > C) with 5 haplotypes and 6 combined genotypes in 3’UTR of SIRT1 gene were identified. In addition, 3 loci were significantly associated with some of the body measurements and meat quality traits in Qinchuan beef cattle(P < 0.05), and the H2H2(GG-AA-CC) diplotypes had better performance than other combinations in Qinchuan beef cattle.Real-time polymerase chain reaction(RT-PCR) results showed that among all types of tissue that were analyzed, the highest m RNA expression levels of the gene were found in subcutaneous fat. DNA sequencing of 468 individuals Qinchuan beef cattle identified two novel, single nucleotide polymorphism(g.19501 C > T and g.19518 C > T) in the 3’untranslated region(3’UTR) of the SIRT2 gene. The frequencies of SNP g.19501 C > T and g.19518 C > T were in Hardy-Weinberg disequilibrium in all the samples. An association analysis showed that the two loci were significantly correlated with some body size traits and the H2H2(-CT-CT-) diplotypes performed better performance than other combinations.Two SNPs(g.22522 C > T and g.22680 C > G) were identified in intron 7 and 3’UTR, via sequencing technology conducted in 679 individual Qinchuan beef cattle. Four different haplotypes were identified, of which the most haplotype had a frequency of 56.2%(-TC-). Based on the ?2 test, the genotypic distributions of the 2 SNPs were in Hardy-Weinberg equilibrium(P < 0.05). At g.22522 C > T locus, the individuals with TT genotype had higher body length, hip width and rump length than those with CC genotype. At g.22680 C > G locus, the individuals with CC genotype had higher body length, hip width, rump length, chest circumference and backfat thickness than those with GG genotype. The H3H3(CT-CC) diplotype had better performance than other combinations.We identified 2 SNPs(g.16195 C > A and g.16247 A > G) in the 3’UTR of the SIRT4 gene from 468 Qinchuan beef cattle by PCR-RFLP and investigated their association with growth and meat quality traits. Based on the ?2 test, the genotypic distributions of the g.16247 A > G was not in Hardy-Weinberg equilibrium(P < 0.01). Association analysis of individual SNPs and haplotype combinations revealed that the individuals with GG genotype had higher body length, rump length, chest depth and chest circumference than those with AA genotype at g.16247 A > G locus(P < 0.05). The H4H3(AA-AG) diplotypes had better performance than H1H2(CA-CG) in body length, rump length, hip width, chest depth, chest circumference and backfat thickness(P < 0.05).We identified 4 SNPs(g.22010 G > A, g.22052 G > A, g.22119 G > T, and g.22245 G > C) in the 3’UTR of the SIRT5 gene from 572 Qinchuan beef cattle by sequencing and investigated their association with growth and meat quality traits. The frequencies of genotype GG and allele G were higher at the 4 SNPs. Based on the ?2 test, the genotypic distributions of the 4 SNPs were not in Hardy-Weinberg equilibrium(P < 0.05). Association analysis of individual SNPs and haplotype combinations revealed that the 4 loci were significantly associated with some body measurement and ultrasound traits in Qinchuan beef cattle, and the H1H5(AG-GA-GG-GG) diplotypes had better performance than other combinations in Qinchuan beef cattle.Four SNPs including g.8384 C > A, g.8460 G > A, g.9429 C > T, and g.9735 T > C were identified in intron 6, exon 7, exon 9, and 3’UTR, via sequencing technology conducted in 468 individual Qinchuan beef cattle. Eleven different haplotypes were identified, of which two major haplotypes had a frequency of 45.7%(-CACT-) and 14.8%(-CGTC-). Based on the ?2 test, the genotypic distributions of g.8384 C > A, g.8460 G > A, and g.9735 T > C were in Hardy-Weinberg equilibrium(P < 0.05). The statistical analyses indicated that g.8460 G > A, g.9429 C > T, and g.9735 T > C were significantly associated with some of the growth and meat quality traits(P < 0.05 or P < 0.01), and the H2H7(CC-GA-TT-TC) diplotype had better performance than other combinations.Two SNPs(g.4556 C > T and g.4762 T > C) were identified in intron 6 and intron 7, via PCR-RFLP conducted in 468 individual Qinchuan beef cattle. Four different haplotypes were identified, of which the most haplotype had a frequency of 57.0%(-TT-). At g.4556 C > T locus, the individuals with CC genotype had higher hip width and ultrasound lean muscle area than those with CT genotype. At g.4762 T > C locus, the individuals with TT genotype had higher body length, hip width, chest circumference and ultrasound lean muscle area than those with CC genotype. The H4H2(CT-TC) diplotype had better performance than other combinations in body length, hip width, chest circumference and ultrasound lean muscle area.A total of eight SNPs were identified within sirtuins genes promoter region, including two SNPs in SIRT2 promoter region(g.-151 C > G and g.-190 A > G), three SNPs in SIRT3 promoter region(g.-725 G > A, g.-772 T > G and g.-910 G > A), one in SIRT4 promoter region(g.-1792 C > A) and three SNPs in SIRT5 promoter region(g.-225 T > A, g.-236 G > C and g.-317 T > C), via DNA sequencing conducted in 413 individual Qinchuan beef cattle. The statistical analyses indicated that AG was superior genotype at g.-190 A > G locus, and the H1H2(CA-CG) diplotype had better performance than other combinations in body length, waist height, rump length, chest depth, chest circumference and backfat thickness in SIRT2 gene. For SIRT3 gene, GG(g.-725 G > A), GG(g.-772 T > G) and GA(g.-910 G > A) were superior genotypes, and the H1H3(ATG-AGG) diplotype had better performance than H3H3(AGG-AGG) in body length, hip width, chest depth and ultrasound lean muscle area(P < 0.05). For SIRT4 gene, GA was superior genotype at g.-1792 C > A locus. For SIRT5 gene, TA(g.-225 T > A), GG(g.-236 G > C) and TC(g.-317 T > C) were superior genotypes), and the H3H1(AGT-ACT) diplotype had better performance than H4H4(TCT-TCT) in body length, rump length, hip width, chest circumference and ultrasound lean muscle area(P < 0.05). |
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