To determine the origin and genetic diversity of Chinese cattle, we analyzed the complete mtDNA D-loop sequences of 84 cattle from 14 breeds/populations from southwest and west China, together with the available cattle sequences in GenBank. Our results showed that the Chinese cattle samples converged into two main groups, which correspond to the two species Bos taurus and Bos indicus. Although a dominant lineage was clearly discerned in both B. taurus and B. indicus mtDNAs, network analysis of the lineages in each of the two species further revealed multiple clades that presented regional diVerence. The B. taurus samples in China could be grouped into clades T2, T3, and T4, whereas B. indicus harbored two clades I1 and I2. Age estimation of these discerned clades showed a time range of 14,100-44,500 years before present (YBP). The phylogenetic pattern of Chinese cattle was consistent with the recently described cattle matrilineal pool from northeast Asia, but suggested that B. indicus contributed more to the cattle from south and southwest China. The genetic diversity of Chinese cattle varied among the breeds studied.

The mitochondrial DNA (mtDNA) D-loop sequences with 399 bp in 26 individuals from 5 donkey breeds in China were analyzed. Aligned by Clustal W software, the results showed that 23 polymorphic nucleotide sites and only transition with the percentage of 5.76% in 399 bp were observed. In reference to mtDNA D-loop sequences of European domestic donkey as a control, the average percentage of mtDNA D-loop nucleotide variation in 5 Chinese donkey breeds was 1.80%. The average percentages of D-loop nucle otide variation from Liangzhou donkey (LZ), Yunan donkey (YN), Guanzhong donkey (GZ), Xinjiang donkey (XJ) and Jiamidonkey (JM) WERE 0.35%, 125%, 2.30, 2.91% and 2.20% respectively. The average sequence divergence estimated from D-loop sequences varied from 0.25%～5.01% within breeds and 4.51%～5.51% among breeds, respectively, demonstrating that there existed rather abundant mitochondrial enetic diversity in Chinese donkeys. Comparisons of the 26 sequences revealed 11 mitochondrial haplotypes: the percentage of haplotype was 42.31%. This phenomenon demonstrated that the mitochondrial genetic diversity in Chinese donkey breeds is being reduced. It is urgent to protect the genetic resources of Chinese donkey. The molecular phylogenetic tree of mtDNA D-loop sequenceds in 5 Chinese donkey breeds, 6 sequences of Asian wild ass (Equus asinus kiang, Equus asinus kulan, Equus asinus hemionus;) and 4 sequences of European domestic donkeys from GenBank was constructed by Neighbor-Joining method. It was the first time proved in molecular level that the origin of Chinese donkey breds was from African wild ass (Equue africanus africanus somaliensis), not from Asian wild ass as bescribed in the paper.

Two Y chromosome specific microsatellites UMN2404 and UMN0103 were genotyped and assessed for polymorphisms in a total of 423 unrelated males from 25 indigenous Chinese cattle breeds. Consistently, both microsatellites displayed specific indicine and taurine alleles in each bull examined. The indicine and taurine alleles were detected in 248 males (58.6%), and 175 males (41.4%), respectively, although these frequencies varied amongst different breeds examined. The indicine alleles dominated in the southern group (92.4%), while the taurine alleles dominated in the northern group (95.5%). Hainan Island was possibly the site for the origin of Chinese zebu, and Tibetan cattle were probably independently domesticated from another strain of Bos primigenius. The geographical distribution of these frequencies reveals a pattern of male indicine introgression and a hybrid zone of indicine and taurine cattle in China. The declining south-to-north and east-to-west gradient of male indicine introgression in China could be explained by historical data, geographical segregation and temperature and weather conditions.

利用蛋白质电泳、RAPD和微卫星DNA技术，对我国濒危保护动物——人工饲养朱鹧进行遗传多态性研究。结果表明，40只朱鸡在前白蛋白（Pre）、白蛋白（Alb）、后白蛋白（Pa）、运铁蛋白（Tf）共4个蛋白质位点上没有发现多态性。用40个随机引物对40只朱鹮进行RAPD分析，其中35个引物扩增出完全相同的RAPD带纹，仅筛选到5个多态性引物，朱鹮群体的平均带纹相似率为0.86。利用其它物种的22对微卫星引物对30只朱鹩的DNA进行检测，共筛选出4对多态性微卫星引物，扩增出13个等位基因。朱鹩在这4对微卫星位点的平均杂合度为0.3760，平均多态信息含量为0.3382，平均等位基因数为2.075。表明朱鹩人工饲养群体的遗传多态性比发现之初得到了一定程度的恢复，但仍然比较贫乏 [动物学报51（4）：650-656，2005]。

对我国8个黄牛品种22个个体的mtDNA D-loop 区910 bp 全序列进行了分析。结果表明：8个黄牛品种 D-loop 区序列中，A+T 平均含量为61.65%；经比对，共检测到66个核苷酸多态位点，约占核苷酸总数的7.25%；D-loop 全序列突变类型有5种，即转换、颠换、插入、缺失转换与颠换共存，它们分别占核苷酸多态位点的81.82%、6.06%、7.57%、3.03%及1.52%。以欧洲牛mtKNA D-loop 全序列为标准，8个黄牛群体D-loop 的平均核苷酸变异率分3个层次：西镇牛、蒙古牛、黑折花牛及秦川牛的核苷酸变异率最低，分别为0.37%、0.44%、0.52%和0.66%；南阳牛与郏县红牛的核苷酸变异率居中，分中别为1.91%和2.02%；晋南牛与岳阳牛的核苷酸变异率最高，分别为4.47%和4.73%。中国黄牛品种内D-loop 区序列歧异度为0.55%~5.39%，品种间序列歧异度为1.21%~6.59%。在所测黄牛个体中，mtDNA D-loop 序列由19种单倍型组成，单倍型比列为86.36%，说明中国黄牛mtDNA 遗传多态性很丰富。由此构建了中国8个黄牛品种的NJ分子系统树，聚类分析表明：所测黄牛的mtDNA D-loop 序列表现为3个单倍型组，从而提示中国黄牛可能有3个母系起源，以普通牛起源和瘤牛起源为主。