Arranz J J, Bayón Y, San Primitivo F
Departamento de Producción Animal, Universidad de León, 24071 León, Spain.
Genet Sel Evol. 2001 Sep-Oct;33(5):529-42. doi: 10.1186/1297-9686-33-5-529.
Genetic variability at 18 microsatellites was analysed on the basis of individual genotypes in five Spanish breeds of sheep--Churra, Latxa, Castellana, Rasa-Aragonesa and Merino--with Awassi also being studied as a reference breed. The degree of population subdivision calculated between Spanish breeds from F(ST) diversity indices was around 7% of total variability. A high degree of reliability was obtained for individual-breed assignment from the 18 loci by using different approaches among which the Bayesian method provided to be the most efficient, with an accuracy for nine microsatellites of over 99%. Analysis of the Bayesian assignment criterion illustrated the divergence between any one breed and the others, which was highest for Awassi sheep, while no great differences were evident among the Spanish breeds. Relationships between individuals were analysed from the proportion of shared alleles. The resulting dendrogram showed a remarkable breed structure, with the highest level of clustering among members of the Spanish breeds in Latxa and the lowest in Merino sheep, the latter breed exhibiting a peculiar pattern of clustering, with animals grouped into several closely set nodes. Analysis of individual genotypes provided valuable information for understanding intra- and inter-population genetic differences and allowed for a discussion with previously reported results using populations as taxonomic units.
基于五个西班牙绵羊品种（丘拉、拉查、卡斯蒂利亚纳、阿拉贡纳萨和美利奴）个体基因型，分析了18个微卫星的遗传变异性，同时也将阿瓦西羊作为参考品种进行了研究。根据F(ST)多样性指数计算得出的西班牙品种间群体细分程度约占总变异性的7%。通过使用不同方法，从18个位点对个体品种归属进行了高度可靠的判定，其中贝叶斯方法最为有效，9个微卫星的准确率超过99%。对贝叶斯归属标准的分析表明，任何一个品种与其他品种之间都存在差异，阿瓦西羊的差异最大，而西班牙品种之间差异不明显。从共享等位基因比例分析个体间的关系。由此得到的树形图显示出显著的品种结构，拉查品种的西班牙品种成员间聚类程度最高，美利奴羊最低，后者呈现出一种特殊的聚类模式，动物被分组到几个紧密相连的节点中。对个体基因型的分析为理解种群内和种群间的遗传差异提供了有价值的信息，并允许与先前使用种群作为分类单位报告的结果进行讨论。
