| 367cattle (Chinese Simmental n=132, Leiqiong n=74, Yunnan-Highhump n=80, BMY cattle n=81) were randomly sampled in this research. The single nucleotide polymorphisms (SNPs) of CAPN1、CAST、GHR and SCD1genes were detected by PCR-SSCP, and the correlations with carcass traits and meat quality traits were analyzed to provide new information for the selection of better carcass and meat quality traits in beef cattle. The main results are listed as follows:1. Two SNPs of CAPN1gene, A4558G and C4684T, were detected in Chinese Simmental, Leiqiong, Yunnan-Highhump and BMY cattle breeds. The SNP A4558G was located at the coding region, leading to a change from isoleucine to valine. The SNP C4684T was located at intron region. The polymorphism information contents (PIC) based on the SNP C4684T of the4breeds were medium polymorphic, while PIC value based on the SNP A4558G was medium polymorphic only in Chinese Simmental, the other three were low polymorphic. The SNPs A4558G in BMY and C4684T of Leiqiong deviated from Hardy-Weinberg Equilibrium. The SNP A4558G of CAPN1gene correlated significantly with bone weight, rate of carcass meat and ratio of meaty bones (P<0.05), while the SNP C4684T correlated significantly with slaughter weight, carcass weight, bone weight, net meat weight, head weight, forehoof weight, stomach weight, mesenteric oil weight and omentum oil weight (P<0.05). Both SNPs correlated significantly with tenderness, but only SNP A4558G correlated significantly with marbling (P<0.05). The findings demonstrated that the two SNPs may be used as molecular genetic markers for slaughter and meat quality traits of beef.2. One SNP of CAST gene, T595C, was detected in Chinese Simmental, Leiqiong, Yunnan-Highhump and BMY cattle breeds. This SNP did not determine the change in amino acid. Only Leiqiong deviated from Hardy-Weinberg Equilibrium on the SNP T595C. The SNP had significant effect on rate of carcass fat cover and back fat thickness (P<0.05).3. One SNP of GHR gene, T229C, was detected in Chinese Simmental, Leiqiong, Yunnan-Highhump and BMY cattle breeds. Based on this SNP, Chinese Simmental and BMY were medium polymorphic, two native yellow cattle groups were low polymorphic. Only Leiqiong breed was in Hardy-Weinberg Equilibrium on this SNP. The SNP had significant effect on muscle development, including slaughter weight, carcass weight, dressing percentage, net meat rate, ratio of Meaty bones, head weight, forehoof weight, hindhoof weight, rate of fat cover, tenderness and marbling(P<0.05), demonstrating that GHR gene could be a candidate gene for selecting on slaughter and meat quality trait of beef..4. One SNP of SCD1gene, C878T, leading to a change in amino acid from Ala to Val, was detected in Chinese Simmental, Leiqiong, Yunnan-Highhump and BMY cattle breeds. Based on this SNP, Leiqiong cattle was low polymorphic, while the other three were medium polymorphic. Yunnan-Gaofeng and BMY deviated from Hardy-Weinberg Equilibrium, while Chinese Simmental and Leiqiong did not. This SNP had significant effect on mesenteric oil weight and back fat thickness (P<0.05).5. The combining effect of all these genes was further analyzed. Based on the above mentioned SNPs, the individuals with a genotype of AA-CT-CT-TT-CT or AA-CT-CT-TT-CT had higher dressing percentage, net beef percentage, and higher tenderness(P<0.05). The findings seemed beneficial to improve carcass and meat quality traits based on selecting certain combination of genotypes. Otherwise, the genotype of AG-CT-CT-TT-CC or AG-CT-CT-TT-CT had an inferior performance in carcass and meat quality traits. |
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