| The genetic diversity of 20 microsatellite loci was analyzed with the microsatellite marker technology in six duck populations. The six populations concluded: Peking duck (Z1 and Z4), Cherry Valley duck, Aobaixing duck, Shaoxing duck and Muscovy duck. The thesis discussed the genetic variation within population and among populations. Allele gene frequency, mean heterozygosisty, effective number of alleles, PIC, the Nei standard genetic distance and D_A genetic distance were calculated. Clustering dendrograms were obtained from Ds and D_A genetic distance. The results were as follows: 1. The 20 microsatellite loci were selected and the results of the PCR in 300 samples of the 6 duck populations were got in every locus. 281 alleles were tested in all the loci and the mean allelic number of per locus was 14, the least locus was 10. The efficient allelic number was 104.43. The efficient allelic number was less than the observed allelic number, this was the result of the alleles distributing unequally. And the dominant allele was analyzed, the results showed that the dominant allele was existed in all loci. 2. The Hardy-Weinberg equilibrium analysis revealed that remarkable genetic disequilibrium was showed at all the loci in 6 duck populations. The reasons may be that the excursion occurred in random mating, the random genetic drift and breeding was existed in 6 populations. In those, the breeding was the main reason. 3. The results showed that all of the 20 microsatellite loci had the high diversity, the mean polymorphic information content (PIC) value was between 0.5968~0.8723, which indicated that the 6 populations had abundant genetic diversity. The mean heterozygosisty was between 0.5886~0.8881, showed that the six populations had higher heterozygosisty. 4. The cofficient of gene differentiation was the largest in AJ272581, the value was 0.2185; then the AJ272579, AJ515900 (the value was 0.1748, 0.1047, respectively); the lowest one was AJ515895, its GST value was 0.0205. The result showed that the genetic differentiation among different populations was about 21.85%, 17.78%, 10.47% and 2.05% in the total population heterozygosisty. 5. The Nei,s standard genetic distance and DA genetic distance among the six duck populations were estimated with the DISPAN soft. The dendrograms were drawed with the upper two genetic distances. The reault showed that the dendrogram of DA genetic distance was similar with the origin, geography and character of the six duck populations. The six populations were clustered two groups. In the first group, Peking duck Z4 and Aobaixing duck clustered first, then the Peking duck Z1, Cherry Valley duck, at last, the Shaoxing duck was clustered with them. The Muscovy duck clustered another group. 6. The F-statistic analysis indicated that the FST of different locus varied from 0.0205 (in AJ515895) to 0.2558 (in AJ515896), and the average was 0.0936. The Nm was from 0.7273 (in AJ515896) to 11.9429, the mean was 2.4203. The result of cluster was consisitent with origin, geography, trait character of breed. It was proved that DS and DA genetic distance were appropriate to microsatellite when used to reconstruct phylogenetic tree. The information about population genetic relationship estimated by microsatellite may be useful as an initial guide in evaluating the value of genetic variation, and developing conservation strategies.
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