蒙古羊胸椎数的亲本印记遗传研究

蒙古羊胸椎数的遗传方式具有亲本印记特征。调控这个性状的Ｈｏｍｅｏｂｏｘ基因突变以后由于父系等位基因或母系等位基因的甲基化，使其转录活动停止，导致父系和母系基因组对子代的遗传贡献不相等，从而使子代产生具有父系或母系特征的亲本印记性状。纯繁与正反交实验证明，在蒙古羊胞椎数的遗传过程中，父系多胸椎基因对子代的影响明显大于母系多胸椎基因，分别为３２．４２％和２１．４３％，当正常型与多胸椎型羊分别进行同型交配时，由于基因组印记效应，使部分子代的Ｈｏｍｅｏｂｏｘ突变基因和野生型基因缄默，因而后代群体中出现亲本类型不同的表型，其比例分别为１１．７６％和１９．１９％。利用蒙古羊的亲本印记遗传特点可以指导种羊选育和商品肉羊的杂交优势利用。

RESEARCHES ON CHARACTERS OF PARENTAL IMPRINTING GENETICS OF VERTEBRA NUMBER IN MONGOLIAN SHEEP

Multi-vertebral characters of Mongolia sheep has a feature of parental imprinting.DNA methylation of paternal and maternal alleles in the early stage of embryo development made one of them silence and resulted in unequal contribution of paternal and maternal genomes to the offspring and appeared imprinting characters.The evidences of pure breeding and reciprocal crosses indicated that the effects of paternal genes of multivertebral characters in Mongolian sheep were more significant than that of maternal ones,which were 32.43% and 21.43% respectively .When T13 and T14 individuals associated breed,there were some phenotype differences from parental phenotypes because of imprinting effects,the percentages of these phenotypes were 11.76% and 19.19%,respectively,It indicated that the knowledge about genomic imprinting might be adopted in some pure breed selections and crossbreeding programs in the near future.