PPARA基因对绵羊肌内脂肪沉积的影响及其多态性OA北大核心CSTPCD

The study aims to investigate the effect and mechanism of PPARA on intramuscular fat(IMF)dep-osition,and to search for molecular markers related to IMF deposition in sheep.The experiment was conducted using Small-tail Han sheep(STH)and a hybrid F1 population between Suffolk sheep and Small-tail Han sheep(STH×SFK)as the research object.By measuring their meat quality,the histological structure and fat drop distribution of longissimus dorsi muscle of two sheep populations were compared by H&E staining and Oil Red O staining;qRT-PCR and WB techniques were used to detect the expression differences of PPARA mRNA and protein levels among different populations,and analyze the correlation between PPARA gene and IMF;Sanger sequencing technology was used to detect the PPARA gene SNP site to evaluate the possibility of using it as a genetic marker related to IMF deposition in sheep.The results indicated that the shear force and water loss rate of STH were significantly higher than those of STH×SFK,but pH was extremely significantly lower than that of STH×SFK,marble score of STH was lower than that of STH×SFK population;histological staining showed that STH muscle fibers were thick and tightly arranged,with IMF concentrated in the muscle fiber gaps,and muscle fibers were thin and loose in structure in STH×SFK,and IMF was evenly and widely distributed among muscle cell and muscle fiber spaces,with a higher content.The expression levels of PPARA mRNA in the STH were significantly higher than those in the STH×SFK popula-tion,and PPARA protein expressions of the STH were extremely significantly higher than those of the STH×SFK population.Correlation analysis showed that the expression level of PPARA gene was extremely significantly nega-tively correlated with sheep fat droplet area ratio and pH,extremely significantly positively correlated with shear force and water loss rate,and weakly correlated with marble score.Sanger sequencing results showed that base muta-tions T49885C,T50007C,G50013A,G50835A,G50942A and G51154C occurred in the second intron of PPARA gene in two sheep populations,but no C49885T mutation was detected in the STH population.The analysis of SNP genetic diversity showed that the homozygosity of SNP loci in the population was greater than the heterozygosity,and they were in a medium to low degree of polymorphism in the population;except for the G50835A mutation,all other SNPs were in line with the Hardy-Weinberg equilibrium,and with a stable genetic basis.It was believed that PPARA gene had an important impact on IMF deposition in sheep,and could be used as a potential molecular genetic mark-er for IMF trait selection in sheep.