两个绵羊品种多位点DNA指纹的研究

Studies on Multilocus Fingerprinting in Two Sheep Breeds

利用3种限制性酶Hind Ⅲ，Hae Ⅲ，Hinf Ⅰ和3种微卫星及小卫星DNA探针（GTG）5，（TG）n，M13检测了2个绵羊品种基因组DNA的多样性。结果表明，具有个体特征的DNA指纹获得依赖于酶／探针的结合。Hae Ⅲ，Hinf Ⅰ和3种探针都可产生丰富的DNA指纹带谱。DNA指纹表现了高度的个体特异性和多样性，这种多样性表现在带纹的数目、强度和带纹的分布区域上。Hind Ⅲ与3种探针的结合都不能产生清晰的DNA指纹带谱。以特定片段长度区域统计丁带纹的相似率，在Hae Ⅲ／（TG）n 组合中，黑头绵羊的平均带纹相似率为0．34，欧洲盘羊为0．50．根据带纹相似率，估算了群体平均杂合度为0．83～O．90．用Hae Ⅲ／（TG）n 组合的指纹相似率，估算了两品种间的相似性指数（0．89）和遗传距离（0．29）．

The variabilities of genomic DNA from Black-head sheep and White-horned Hei-dschnucke were detected using multilocus DNA fingerprinting with three restriction enzymes（Hind Ⅲ, Hae Ⅲ and Hinf Ⅰ）and three digoxigenated microsatellite and minisatellite probes [（GTG）5, （TG）n and M13].The results showed that the appearance of informative individual-specific DNA fingerprint bands was dependent on the enzyme-probe-combinations. The Hae Ⅲ and Hinf Ⅰ in connection with used three probes can yield informative DNA fingerprints. DNA fingerprints were individual-specific and showed polymorphism in number, intensity and distributing region of bands among individuals. The Hind Ⅲ was proved to be unsuitable for all investigated enzyme-probe-combinations, The band-sharing rates （BSR） between individuals were determined from the DNA fingerprints. The average band-sharing rates in FLR between 4. 4 and 23. 1 kb were 0. 34 in Black-head sheep and 0.50 in White-horned Heidschnucke. The average probability h for a band to be present in the heterozygous state was calculated among unrelated individuals from band-sharing rates. The values were between 0.83 and 0.90. Indices of between-population similarity （0.89） and genetic distance （0.29） between two sheep breeds were estimated using band-sharing rates in Hae Ⅲ/（TG）n combina tion.