Davis George Henry
AgResearch, Invermay Agricultural Centre, Private Bag, Mosgiel, New Zealand.
Genet Sel Evol. 2005;37 Suppl 1(Suppl 1):S11-23. doi: 10.1186/1297-9686-37-S1-S11.
Research conducted since 1980 in relation to inheritance patterns and DNA testing of major genes for prolificacy has shown that major genes have the potential to significantly increase the reproductive performance of sheep flocks throughout the world. Mutations that increase ovulation rate have been discovered in the BMPR-1B, BMP15 and GDF9 genes, and others are known to exist from the expressed inheritance patterns although the mutations have not yet been located. In the case of BMP15, four different mutations have been discovered but each produces the same phenotype. The modes of inheritance of the different prolificacy genes include autosomal dominant genes with additive effects on ovulation rate (BMPR-1B; Lacaune), autosomal over-dominant genes with infertility in homozygous females (GDF9), X-linked over-dominant genes with infertility in homozygous females (BMP15), and X-linked maternally imprinted genes (FecX2). The size of the effect of one copy of a mutation on ovulation rate ranges from an extra 0.4 ovulations per oestrus for the FecX2 mutation to an extra 1.5 ovulations per oestrus for the BMPR-1B mutation. A commercial DNA testing service enables some of these mutations to be used in genetic improvement programmes based on marker assisted selection.
自1980年以来，针对繁殖力主要基因的遗传模式和DNA检测开展的研究表明，主要基因有潜力显著提高全球绵羊群体的繁殖性能。在骨形态发生蛋白受体1B（BMPR-1B）、骨形态发生蛋白15（BMP15）和生长分化因子9（GDF9）基因中发现了增加排卵率的突变，并且从已表达的遗传模式可知还存在其他突变，尽管这些突变尚未定位。就BMP15而言，已发现四种不同的突变，但每种突变产生相同的表型。不同繁殖力基因的遗传模式包括对排卵率有累加效应的常染色体显性基因（BMPR-1B；拉库内绵羊）、纯合雌性不育的常染色体超显性基因（GDF9）、纯合雌性不育的X连锁超显性基因（BMP15）以及X连锁母系印记基因（FecX2）。一个突变拷贝对排卵率的影响大小范围从FecX2突变每发情期额外增加0.4个排卵数到BMPR-1B突变每发情期额外增加1.5个排卵数。一项商业DNA检测服务使其中一些突变能够用于基于标记辅助选择的遗传改良计划。
