Genetic diversity, population structure and phylogenetic relationships of three indigenous pig breeds from Jiangxi Province, China, in a worldwide panel of pigs.

Dongxiang Spotted, Pingxiang Two-End-Black and Yushan Black pigs are three indigenous breeds in Jiangxi Province, China, that have been listed in the national conservation program for Chinese indigenous livestock germplasm. Here, we investigated the genetic diversity and population structure of the nucleus populations of these three breeds in a worldwide context of European and Chinese pigs using Illumina Porcine 60K chips. Our data indicate that Dongxiang Spotted and Yushan Black pigs have recently experienced severe inbreeding. The two breeds show large runs-of-homozygosity values, long-range extents of linkage disequilibrium and reduced observed heterozygosity. In contrast, Pingxiang Two-End-Black pigs are rich in genetic diversity and have few inbred individuals. Both phylogenetic and admixture analyses illustrate that Dongxiang Spotted and Yushan Black pigs are genetically close to their geographical neighbors in East China and that Pingxiang Two-End-Black pigs have a close relationship with three other Two-End-Black breeds in central China. Finally, we reconstructed the family structures of the three breeds and propose a reliable breeding strategy to better conserve these breeds.