中文摘要：

以8个中国地方绵羊品种和1个外来品种的20个个体为研究对象，通过对Cytb基因的全序列测定，结果表明：绵羊的单倍型多样性为97．1％。所有序列的平均碱基组成为27．1％T，28．5％C，31．4％A及13．0％G，G＋C含量为41．5％，核苷酸多样性为0．602％。在所有序列中共检测到43个变异位点，其中包括40处转换和3处颠换。Fu’S中性检验表明差异不显著（0．10〉P〉0．05），说明绵羊群体未发生群体扩张事件。NJ、ME及UPGMA聚类结果均表明，我国绵羊可分为3个单倍型组，这提示我国绵羊有3个母系起源。

英文摘要：

The complete sequences of Cyt b gene from 20 individuals belonging to eight Chinese indigenous sheep breeds and one foreign breed were studied. The results showed that the hapolotype diversity of Chinese sheep breeds was 97.1%. The mean nucleotide composition of all the sequences was 27.1% T, 28.5% C, 31.4% A, and 13.0% G. The nucleotide diversity was 0.602%. A total of 43 mutation sites were detected, including 40 transitions and 3 transversions. Fu＇s test of selective neutrality showed that the sheep populations had no population demographic expansion （0.10 〉 P 〉 0.05）. The different clustering methods, namely neighbor-joining, minimum evolution, and unweighted pair group method with arithmetic means, all showed a similar result, which indicated that Chinese local sheep had three maternal resources.