| Diverse breeds can ensure domestic animals have adaptability to variable environmental conditions, and are the basis of sustainable development of Livestock Husbandry. China is rich in breed resources of pig, but lots of them are being eroded by exotic commercial pig breeds at the present time, and crisis of indigenous pig breeds has already rose. Studies on genetic diversity of domestic animals will contribute to the maintenance and utilization of breed resources. Microsatellite DNA marker is regarded as a power tool for evaluation of genetic diversity. In this study, genetic diversity of some characteristic indigenous pig breeds (Taihu Pig, Jiangquhai Pig, Dongchuan Pig and miniature Pigs) and Auckland Pig was detected by means of microsatellites, so as to offer some valuable suggestion for conservation of these breeds. At the same time, kinds of analysis ways were applied in order to develop a set of efficient statistic way for microsatellite data. The research results of this study are as the followings,1. Most of twenty-seven microsatellite loci were highly polymorphic in Taihu Pig, Jiangquhai Pig and Dongchuan Pig. Average number of allele per locus was 8.148 and average heterozygosity was 0.722. Hardy-Weinberg equilibrium test indicated genetic drift had occurred in these populations, which might be caused by founder effect, intensive selection and close breeding.2. The number and frequency of allele varied at microsatellite loci for different pig breeds (types). Some alleles were shared by all of seven populations, such as 104bp at Sw24 and HObp at Sw936, which were likely to be the "oldest" and common gene fragments in native pig genome. Some alleles were founded only in a single population, such as 180bp at S0218 in Erhualian and 114bp at Sw72 in Shawutou, which could be considered as distinctive marker for breed verification and breed conservation.3. Expected heteozygosity of seven breeds (types) ranged from 0.429 to 0.677. Jiangquhai Pig had the largest genetic variability, and followed by Mi Pig, Erhualian, Shawutou, Middle Meishan, Dongchuan Pig and Small Meishan. Total genetic differentiation was mostly within population as showed by the fixation index (Fst=0.18).4. Nei's (1972) standard genetic distances of breeds (types) were between 0.238 and 0.624, and Cavalli-Sforza & Edwards (1967) chord distances were between 0.107 and 0.231.Both NJ and UPGMA tree showed that five types of Taihu Pig formed one branch, Jiangquhai Pig and Dongchuan Pig formed another branch. Among Taihu types, Erhualian and Mi Pig grouped closely. Middle Meishan and Small Meishan were clustered firstly, and then with Shawutou. The principal component analysis also demonstrated the similar genetic relationships of these pig breeds (types).5. By combining microsatellite data of European pigs and other Chinese indigenous pigs for cluster analysis, European pig breeds and Chinese pig breeds were divergent with each other distinctively, which supported that European and Asian domestic pigs originated from different kinds of wild boars.6. Genetic diversity of miniature and Erhualian (used as outgroup) was evaluated using twenty fluorescent microsatellites. Expected heteozygosity of five breeds varied from 0.553 to 0.661. The population genetic variability of Tibetan Pig was the largest genetic variability, and followed by Wuzhishan Pig, Diannan Small Ear Pig and Xiang Pig.7. Nei's (1972) standard genetic distances of five breeds (types) were between 0.429 and 0.986, and the similar coefficients were between 0.373 and 0.651. NJ tree showed that Xiang Pig and Diannan Small Ear pig were clustered as one branch, and then with Tibetan pig. Wuzhishan and Erhualian grouped as another branch.8. The NJ tree constructed from allele sharing measure (DAS) of individuals showed, all of individuals of Erhualian, Wuzhishan and Diannan Small Ear pigs were assigned to their resource breeds correctly, and only two of Xiang Pig were assigned to Tibetan Pig. There are two subpopulations in Tibetan Pig and Wuzhishan...
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