Abstract: 【Objective】To reveal the genetic diversity and phylogenetic relationship of china donkey breeds, 【Method】 the genetic polymorphisms of 24 microsatellites in 8 china large and middle-sized donkeys were studied by means of PCR polyacrylamide gel electrophoresis and silver staining. Number of alleles, average effective number of alleles (E) and average rates of homozygote of each breeds were counted. According to allele frequencies of 24 microsatellites, polymorphism information content(PIC),mean heterozygosity (h) and genetic distances (DA) were calculated for each breeds, By using the Neighbour-joinig method of Dispan software, the polymorphic trees were constructed based on genetic distances. The systematic relation was analyzed as well. 【Result】The results showed that NVHEQ18 is medium polymorphic and the other 23 of 24 microsatellite loci were highly polymorphic, The average PIC (0.6940), h (0.7119) and E (2.9) of the eight donkey breed population were all higher ,which showed the gene polymorphisms and genetic diversity were higher. Guanzhong donkey、Jinnan donkey、Guangling donkey and Dezhou donkey of large breeds and Qingyang donkey of middle-sized clustered in one group and Biyang donkey、Huaiyang donkey and Jiami donkey of middle-sized clustered in another groups. The phylogenetic relationship between different breeds were in accordance with their breeding history and distribution. 【Conclusion】The 24 microsatellite loci were effective markers for analysis of genetic relationship among donkey breeds.

Key words: Donkey, Microsatellite, Genetic diversity, Phylogenetic relationship