Analysis of Genetic Diversity and Population Structure of Liangshan Black Pigs, a New Indigenous Pig Breed in Shandong Province

Liangshan Black pigs are a new Chinese indigenous breed discovered during the Third National Survey of Livestock and Plant Genetic Resources. To uncover genetic diversity, population structure, and potential exotic introgression in this breed, we sampled 191 Liangshan Black pigs from the conservation population and genotyped these individuals using the “Zhongxin-I” porcine chip, then conducted in-depth population genetic analyses in the context of pigs from five introduced breeds. The results revealed that the tested individuals exhibited significant genetic diversity, displayed uneven kinship relationships, and were assigned to nine families according to their clustering patterns in the phylogenetic tree. Further relationship analyses with the five introduced breeds demonstrated that Liangshan Black pigs were clustered separately from the introduced breeds, had larger evolutionary distances with the introduced breeds, and possessed certain genetic components of the introduced breeds, especially those of Duroc. These findings demonstrate that Liangshan Black pigs are generally an indigenous breed independent of the introduced breeds but are slightly affected by the introduced breeds. In summary, the results of our study not only contribute to an in-depth understanding of the population genetic characteristics of Liangshan Black pigs but also provide the necessary data for the implementation of conservation programs.