猪UCP3基因多态性及其与脂肪沉积、肉质性状的相关分析

在QTL定位的基础上选取猪解偶联蛋白3(UCP3)作为控制脂肪沉积性状和肉质性状的候选基因。对猪UCP3基因的部分编码区进行了测序，在395 bp处发现了1个cSNP位点。该cSNP位点发生G→A突变，并导致相应编码氨基酸由甘氨酸→精氨酸的改变。该位点可以被限制性内切酶SmaⅠ识别。利用PCR-RFLP方法，对186头大白×梅山F2资源家系进行UCP3片段SmaⅠ位点分析，发现AA、AB和BB三种基因型，其中A等位基因频率0.56，B 0.44。经统计分析发现，在该F2群体中，UCP3 SmaⅠ位点多态性与脂肪沉积性状中胸腰椎间膘厚、臀部膘厚显著相关；与肉质性状中的肌内脂肪、系水力和失水率显著相关。UCP3 SmaⅠ位点主要表现为加性效应，基因型AA降低膘厚，提高系水力和降低失水率，但同时也降低肌内脂肪含量。

Polymorphism of Porcine Uncoupling Protein 3 (UCP3) and Its Association with Fat Deposition and Meat Quality

Based on quantitative traits loci (QTL) mapping, porcine uncoupling protein 3 (UCP3) gene was chosen as a candidate gene for pig fat deposition and meat quality traits. Partial coding region of UCP3 gene was sequenced and there was one single nucleotide polymorphisms (cSNP) at 395 bp. This mutation was G→A and it resulted in the amino acid change from glycine to arginine. This site was also recognized by restriction endonuclease SmaⅠ. The polymorphism of the UCP3 SmaⅠwas analyzed with PCR-RFLP among 186 Large white × Meishan F2 progeny. The genotypes of UCP3 SmaⅠwere AA, AB and BB. The frequency of A allele was 0.56 and B was 0.44. With statistical analysis, it was found that the SmaⅠ polymorphism in the F2 population was significant associated with backfat thickness at thorax-waist and at buttock, intramuscular fat, drip loss rate and water holding capacity. The function of UCP3 SmaⅠmainly showed additive effect. The genotype AA reduced back-fat thickness and water drip loss rate, and increased water holding capacity. Meanwhile, it also decreased the intramuscular fat content .