北京黑猪MYH3和MYH13基因多态性与肉质性状的关联分析

【目的】 试验旨在研究肌球蛋白重链3（myosin heavy chain 3，MYH3）和肌球蛋白重链13（myosin heavy chain 13，MYH13）基因遗传变异对猪肉质性状的影响。【方法】 利用北京黑猪背最长肌样本进行肉质性状（肌内脂肪（intramuscular fat，IMF）、水分、滴水损失、酸碱度（pH）、肉色L^*值、肉色a^*值和肉色b^*值）表型数据的测定。利用PCR和Sanger测序技术对MYH3和MYH13基因启动子区和CDS区进行基因分型。将性别、场、日龄作为协变量，采用协方差分析，确定与猪肉质性状相关的SNPs，利用实时荧光定量PCR检测基因表达水平。【结果】 试验共筛选到9个SNPs，其中MYH3基因CDS区有1个错义突变（c.5782 G>C）与IMF显著相关（P<0.05），且MYH3基因表达水平与IMF呈正相关；MYH13基因CDS区有4个SNPs，其中2个（c.1923 G>A、c.1308 G>A）与肉色a^*值显著相关，1个（c.963 G>A）与滴水损失显著相关，1个（c.237 G>T）与肉色L^*值显著相关（P<0.05）；MYH13基因启动子区有4个SNPs，其中2个（rs699287502、rs318639161）与肉色L^*值显著相关，2个（rs321315318、rs330770991）与滴水损失显著相关（P<0.05），且MYH13基因表达水平与滴水损失呈负相关。【结论】 MYH3基因有1个SNP与IMF显著相关，且其基因表达水平与IMF呈正相关。MYH13基因中存在3个SNPs与滴水损失显著相关，且该基因启动子区2个SNPs基因表达水平与滴水损失呈负相关；3个SNPs与肉色L^*值显著相关；2个SNPs与肉色a^*值显著相关。以上SNPs均可作为影响北京黑猪肉质性状的候选基因功能位点。

Association Analysis of Polymorphism of MYH3 and MYH13 Genes with Meat Quality Traits in Beijing Black Pigs

【Objective】 The aim of this study was to investigate the effects of genetic variation of myosin heavy chain 3 (MYH3) and myosin heavy chain 13 (MYH13) on meat quality traits in pigs.【Method】 The meat quality traits (intramuscular fat (IMF), moisture, drip loss, pH, meat color (L^*, a^* and b^* values)) of longissimus dorsi muscle samples in Beijing Black pigs were measured.The promoter and CDS regions of MYH3 and MYH13 genes were genotyped by PCR and Sanger sequencing.The SNPs associated with meat quality traits were determined by covariance analysis using sex, field and age as covariates, the expression of MYH3 and MYH13 genes were detected by Real-time quantitative PCR.【Result】 A total of nine SNPs were screened in this study.There was a missense mutation (c.5782 G>C) in CDS region of MYH3 gene, which was significantly correlated with IMF content (P<0.05), the expression of MYH3 gene was positively correlated with IMF content.There were four SNPs in CDS region of MYH13 gene, of which two SNPs (c.1923 G>A and c.1308 G>A) were significantly correlated with meat color a^*value, one SNP (c.963 G>A) was significantly correlated with drip loss, one SNP (c.237 G>T) was significantly associated with meat color L^* value (P<0.05).There were four SNPs in promoter region of MYH13 gene, two SNPs (rs699287502 and rs318639161) were significantly associated with meat color L^* value, two SNPs (rs321315318 and rs330770991) were significantly related to drip loss (P<0.05), and the expression of MYH13 gene was negatively correlated with drip loss.【Conclusion】 One SNP of MYH3 gene was significantly associated with IMF, and its gene expression was positively correlated with IMF content.Three SNPs of MYH13 gene were significantly associated with drip loss, the expression of two SNPs of MYH13 gene promoter region was negatively correlated with drip loss.Three SNPs of MYH13 gene were significantly associated with meat color L^* value, two SNPs of MYH13 gene were significantly associated with meat color a^* value.These SNPs could be used as candidate gene functional loci for meat quality traits in Beijing Black pigs.