利用微卫星DNA多态性预测引进肉用绵羊品种杂种优势

【目的】利用微卫星DNA在不同绵羊群体中的多态性预测引进肉用绵羊品种与小尾寒羊的杂种优势。【方法】利用5个微卫星基因座对4个国外引进肉羊品种及小尾寒羊5个群体的等位基因频率、群体多态信息含量、有效等位基因数、杂合度和遗传距离进行了遗传检测，并测定4个引进肉羊与小尾寒的杂交效果。【结果】5个微卫星基因座在白头萨福克、黑头萨福克、道赛特、得克赛儿及小尾寒羊5个群体中存在多态性，可以用于绵羊遗传多样性的评估；从不同品种看，道赛特羊的遗传变异程度最大，而小尾寒羊的遗传变异程度相对较小；经遗传关系分析，在引进的4个肉羊品种中，与小尾寒羊杂交优势由大到小依次为白头萨福克、黑头萨福克、道赛特、得克赛儿，与实际杂种优势测定结果相符。【结论】利用微卫星DNA多态性预测引进肉用绵羊品种与小尾寒羊的杂种优势是可行的，将对今后绵羊育种具有重要的应用价值。

Forecast of Heterosis of Introduced Meat Sheep by Genetic Polymorphism of Microsatellite DNA

Objective] Forecast of the heterosis of Small Tail Han Sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA was made in different sheep breeds. Method] Gene frequency, polymorphism information contents, number of effective alleles, heterozygosity and genetic distances were studied in four imported meat sheep and Small Tail Han Sheep using five microsatellite loci. The crossing effects on Small Tail Han Sheep with four imported meat sheep were tested. Result ] The results indicate that there are genetic polymorphisms at five microsatellite loci in five sheep breeds. Five microsatellite loci can be used for genetic diversity evaluation in sheep breeds. The genetic variability of Dorset is the highest, and Small Tail Han Sheep is the lowest in five sheep breeds. The order of heterosis from large to small in four imported meat sheep by the analysis of genetic relationship is White-Suffolk, Black-Suffolk, Dorset, Texel. It accords with testing results on actual heterosis. Conclusion] It is feasible to forecast the heterosis of Small Tail Han Sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA and it will have an important value for sheep breeding in future.