中国美利奴羊H-FABP基因多态性及其与部分肉质性状的相关性

利用聚合酶链式反应-单链构象多态（PCR-SSCP）技术检测中国美利奴羊（Ovis aries var. Merino）心型脂肪酸结合蛋白基因（H-FABP）外显子2的单核苷酸多态性（SNPs）和遗传多态性，分析其与肌内脂肪（IMF）含量、肌纤维直径和肌纤维密度的相互关系，为该品种绵羊的分子标记辅助选择提供理论依据。结果显示，H-FABP基因外显子2有AA、AB和BB 3种基因型，AA型和BB型在778位均发生了C缺失，939位均发生了A→G转换，BB型还在789位发生了T→C转换，该突变导致所编码氨基酸发生了缬氨酸→丙氨酸的替换；BB型为IMF的优势基因型，与AB型相比差异显著（P<0.05），与AA型相比差异极显著（P<0.01）；BB型对肌纤维直径存在负相关。结果提示，中国美利奴羊H-FABP基因外显子2具有多态性，该基因可能是中国美利奴羊肉质性状的主效基因，或者与控制肉质性状的主效基因相连锁。

Single Nucleotide Polymorphism of H-FABP Gene and Its Correlation with Meat Quality Traits in Merino Sheep

In order to analyze the single nucleotide polymorphisms (SNPs) in the extron 2 of heart fatty acid binding protein gene (H-FABP) and its relationship with some meat quality traits in Merino Sheep (Ovis aries var. Merino), and to provide a theoretical foundation for the marker-assisted selection, we measured intramuscular fat (IMF) content, muscle fiber diameter and muscle fiber density of 150 Merino sheep, and used polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique to analyze the SNPs at the exon 2 of the H-FABP gene. It was shown that the exon 2 of H-FABP gene displayed AA, AB and BB genotypes. There were mutation of 939(A/G) and deletion of C in both AA and BB genotypes, and 789 (T/C) in BB genotype, which led to valine convertion to alanine. The BB genotype was advantageous genotype of IMF and there were significant difference between BB and AB (P<0.05), and extremely significant difference (P<0.01) between BB and AA. The correlation of BB genotype and muscle fiber diameter was negative. These results indicate that the exon 2 of H-FABP gene of Merino Sheep shows polymorphism and that H-FABP gene may be a major gene or a major gene-linked gene for meat quality of Merino Sheep.