肉用动物双肌性状的研究现状

综述肉用动物双肌性状的形态、生理生化、组织学、遗传机制及其对相关性状影响等方面的研究。牛双肌基因位于第２号常染色体上，是由ｍｙｏｓｔａｔｉｎ基因在第３外显子处核苷酸突变造成的，为不完全显性遗传；羊ｃａｌｉｐｙｇｅ突变基因定位于第１８号染色体上，以非孟德尔方式遗传，被称做极性超显性。双肌动物的瘦肉率、瘦肉量、肉骨比显著高于普通动物，而其脂肪率较低、繁殖性能较差并对应激更敏感。双肌基因在生产中主要通过将双肌动物作为终端杂交父本来应用。

Muscular Hypertrophy in Meat Animals

The studies on muscular hypertrophy in morphology, physiology, biochemistry, histology, its determents of heredity, and its effects on relative traits in meat animals are reviewed. The results show that a major gene is involved in the determination of muscular hypertrophy in cattle, which is positioned on chromosome 2 and inherited in partially recessive mode, because a mutant happened in the third exon on the myostatin sequence. The callipyge gene has been mapped to chromosome 18, and its phenotype is characterized by nonMendelian inheritance pattern, referred to as polar overdominance. The carcass lean percentage, the percentage of hypertrophied muscle and muscle:bone ratio in animals with muscular hypertrophy are significantly higher than in normal animals, whereas with lower carcass fat percentage, bitter fertility and greater susceptibility than normal animals. The best way to use mh gene in meat production is to use the male animals with muscular hypertrophy as the terminal sire to cross with