Polymorphism of porcine uncoupling protein 3 (UCP3) and association with fat deposition and meat quality

Based on quantitative trait locus (QTL) mapping, the gene for porcine uncoupling protein 3 ( UCP3 ) was chosen as a candidate gene for pig fat deposition and meat quality traits. In this study, a partial coding region of the UCP3 gene was sequenced and one single nucleotide polymorphism (cSNP) was found at 395 bp. The mutation was G→A and resulted in the amino acid change from glycine to arginine. This site was also recognized by restriction endonuclease Sma I. The UCP3 Sma I polymorphism was analysed among 186 individuals of Large White×Meishan F 2 progeny using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). The genotypes of the UCP3 Sma I polymorphism were AA, AB and BB. The frequency of A and B alleles was respectively 0.56 and 0.44. Statistical analyses showed that the Sma I polymorphism in the F 2 population was significantly associated with back-fat thickness at thorax–waist and buttock, as well as with intramuscular fat, drip-loss rate and water-holding capacity. The additive effect of UCP3 Sma I was clearly shown. The genotype AA reduced back-fat thickness and drip-loss rate, increased water-holding capacity, and decreased the intramuscular fat. The effect of the pig UCP3 Sma I polymorphism needs to be analysed in other populations using larger samples.