Effects of the beta-adrenergic receptor gene polymorphisms on porcine subcutaneous fat layer thickness

测定了梅山猪、杜洛克猪和长白猪肾上腺素能受体Beta1、Beta2和Beta3基因(ADRB1、ADRB2和ADRB3)的全长氨基酸编码序列。在猪ADRB1基因中发现Arg458Pro非同义替换，编码469个氨基酸序列。在猪ADRB2基因中发现了Asn29Asp和Glu30Gln的连续替换，编码418个氨基酸序列。猪ADRB3基因存在Glu24Thr、Arg264Glu和Glu398Asp三个非同义突变。梅山猪在ADRB3基因中插入胸腺嘧啶，导致两个氨基酸的蛋白质变短。为了评估ADRB变异对猪皮下脂肪层厚度的影响，计算了脂肪和瘦肉组的遗传频率，每组包括杜洛克猪和金华猪杂交猪各24头。ADRB3基因无足够变异，经x^2检验，两组ADRB1、ADBR2基因差异无统计学意义。而ADRB1基因Arg458纯合子在瘦肉组高于Pro458变异体，脂肪层稍薄。ADRB2的Asp29-Lys30基因型在瘦肉组较高，Asn29-Glu30基因型在肥胖组较高。这些结果表明ADRB基因多态性是影响猪皮下脂肪层厚度的次要因素。

The full amino acid coding sequences of adrenergic receptor beta1, beta2, and beta3 (ADRB1, ADRB2, and ADRB3) genes were determined from Meishan, Duroc, and Landrace pigs. Non-synonymous substitution of Arg458Pro was found in the pig ADRB1 gene coding a 469 amino acids sequence. Continuous substitutions of Asn29Asp and Glu30Gln were found in the pig ADRB2 gene coding a 418 amino acid sequence. There were three non-synonymous substitutions of Glu24Thr, Arg264Glu and Glu398Asp in the pig ADRB3 gene. A thymine insertion in ADRB3 gene resulting in two amino acids shorter protein was found in Meishan pigs.To assess the effects of ADRB variants on porcine subcutaneous fat layer thickness, genetic frequency of the variants were calculated in fatty and lean groups, consisted of each 24 animals of the crossbred of Duroc and Jinhua pigs. There was no sufficient variation in the ADRB3 gene, and x^2 test showed no significant difference in the ADRB1 and ADBR2 genes of the two groups. However, Arg458 homozygotes of ADRB1 were higher in lean group and had a little thin fat layer than Pro458 variant. The Asp29-Lys30 genotypes of ADRB2 were higher in lean group, and theAsn29-Glu30 genotypes were higher in fatty group. These results suggested that ADRB polymorphism is a minor factor for porcine subcutaneous fat layer thickness.