Insights into the genetic diversity of indigenous goats and their conservation priorities.

Objective: An experiment was conducted to evaluate genetic diversity of 26 Chinese indigenous goats by 30 microsatellite markers, and then to define conservation priorities to set up the protection programs according to the weight given to within- and between-breed genetic diversity. Methods: Twenty-six representative populations of Chinese indigenous goats, 1351 total, were sampled from different geographic regions of China. Within-breed genetic diversity and marker polymorphism were estimated calculating the mean number of alleles (MNA), observed heterozygosities (HO), expected heterozygosities (He), fixation index (FIS), effective number of alleles (NE) and allelic richness (Rt). Conservation priorities were analyzed by statistical methods. Results: A relatively high level of genetic diversity was found in twenty-four populations, the exceptions were in the Daiyun and Fuqing goat populations. Within-breed kinship coefficients matrix identified seven highly inbred breeds which should be concerned. Of these, six breeds will get a negative contribution to heterozygosity when the method was based on proportional contribution to heterozygosity. Based on Weitzman or Piyasatian and Kinghorn methods, the breeds distant from others i.e. Inner Mongolia Cashmere goat, Chengdu Brown goat and Leizhou goat will obtain a high ranking. Evidence from Caballero and Toro and Fabuel et al. method prioritized Jining Gray goat, Liaoning Cashmere goat and Inner Mongolia Cashmere goat, that in agreement with results from Kinship-based methods. Conclusion: Conservation priorities had planned according to multiple methods. Our results suggest Inner Mongolia Cashmere goat (most methods), Jining Gray goat and Liaoning Cashmere goat (high contribution to heterozygosity and total diversity) should be prioritized based on most methods. Furthermore, Daiyun goat and Shannan White goat also should be prioritized based on consideration of effective population size. However, if one breed could survive in changing conditions all the time, the straightforward approach is to increase its utilization and attraction for production via mining breed germplasm characteristic.

[Genetic diversity of seven miniature pig breeds (strains) analyzed by using microsatellite markers].

Twenty-seven microsatellite markers recommended by the Food and Agriculture Organization (FAO) and the International Society for Animal Genetics (ISAG) were used to analyze the genetic diversities of 7 Chinese native miniature pig breeds/strains (Jiuyang Xiang Pig, Jianbai Xiang Pig, Congjiang Xiang Pig, Huanjiang Xiang Pig, Black Xiang Pig, Wuzhishan Pig, and Diannan Small Ear Pig) and 3 western pig breeds (Duroc, Large White, and Landrace). The results indicate that there exists, in general, a high degree of genetic variability within the 7 miniature pig breeds. However, the genetic variability in Jiuyang Xiang Pig, Jianbai Xiang Pig, Huanjiang Xiang Pig, and Congjiang Xiang Pig (average PICs being 0.61-0.64) was significantly lower than that in the other three miniature pig breeds (average PICs being 0.60-0.84). The genetic divergence among Jiuyang, Jianbai, Huanjiang, and Congjiang was very small (Nei's standard genetic distances being 0.12-0.22), but it was large between them and the other three miniature pig breeds (Nei's standard genetic distances being 1.61-1.96), and even larger between them and the three foreign breeds (Nei's standard genetic distances being 1.99-3.30). Cluster analysis reveals three obvious clusters for the 10 breeds: Jiuyang, Jianbai, Huanjiang, and Congjiang are in one cluster, the other three miniature pig breeds in the other, and the three foreign breeds in the third. These results are consistent with the geography distribution and origin of these breeds.

Genetic diversity of microsatellite loci in fifty-six Chinese native pig breeds.

The genetic diversity of fifty-six indigenous pig breeds in China, and three introduced pig breeds (Duroc, Landrace and Large White) was surveyed using twenty-seven microsatellites recommended by the International Society for Animal Genetics (IS-AG) and Food and Agriculture Organization (FAO). By means of the allele frequencies, mean heterozygosity, effective number of alleles, estimator of gene differentiation, polymorphism information content, genetic distance and dendrogram analysis, the genetic variability and population structure of native pig breeds were estimated. Genetic variabilities within native pig breeds are as follows: Effective number of alleles vary from 2.12 to 9.03, from 0.44 to 0.87 for mean heterozygosity, from 0.39 to 0.86 for polymorphism information content. Nei's genetic distance and Nei's standard genetic distance were estimated and used to construct UPGMA and NJ dendrograms, which were evaluated by the bootstrap test. Fifty-six Chinese indigenous pig breeds were clustered into twelve groups based on the dendrogram. Compared with the classification in Pig Breeds in China, I, II and III groups in the study are equivalent to North-China type, IV group basically accords with Lower-Changjiang River Basin type, V, VI, VII, VIII and IX groups quite correspond with Central-China type, X and XI group largely correspond to South-China type, the last group, XII is equal to South-west type at large. Suggestions that the conservation farms together with conservation areas are appropriate methods for the preservation of native pig breeds in our country were proposed. The results could provide basic molecular data for the research on the germplasm characteristics of local breeds in our country and scientific basis for the conservation and utilization of those breeds.