草食家畜双肌基因研究进展

牛双肌(Double-muscular)基因位于第2号染色体上,是由myoststin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;绵羊Cfllipyge突变基因定位于第18号染色体上,以非孟德尔方式遗传,称为极性超显性。双肌动物的瘦肉率显著高于普通动物,而其脂肪含量低,繁殖性能较差并对应激更敏感。本文从遗传方式、基因座的定位、遗传效应、作用机理及在动物育种中的应用等方面,对引起绵羊双肌臀性状的Cfllipyge基因与引起牛双肌性状的Double-muscular基因进行了阐述,并就其今后的开发利用进行了探讨。

Muscular Hypertrophy in Grazing 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 2and inherited in partially recessive mode,because a mutant hap pened in the third exon on the myostatin se quence.The callipyge gene has been mapped to chromosome 18,and its phenotype is charac terized by non-Mendelian in heritance 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,bitterfertility 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 the normal female an imals.