The Genetic Diversity Of Tibetan Pig MC1R Gene Research

China had been one of the most important pork producers around the world, having numerous consumers, as it’s possess of.However. lagging breeding management have resulted in a large scale introduction of European commercial germplasm into China by a large number of farming enterprises to meet meat requirement. In this context, to performgenetic resources diversity research and to carry out breed conservation works would be remarkably important.Coat color, as one of the classic complex quantitative traits.was regulated by both genetic (multiple genes) and environmental factors. Coat color have not received much attention of breeders until recent years. To identify the genetic of this trait can be used to determine the hybridcombination and the purity of given breed.Tibetan pigs, one of Chinese local pig breeds that have black coat color, are primarily distributed in the mountainous grassland, low bulrush meadows and the valley zone of a large high altitude area in Southwest China. Melanocortin receptor 1(MC1R) gene is the major genetic component that responsible for thecoat color variation.Given the possession of a relatively small population of Tibetan pig and the particularity of its high-altitude living environment, to study the genetic polymorphisms of MCIR in Tibetan pigs will be of great significance.To gain a insight into the genetic diversity and the relationship between the different pig breeds, in this study, we cloned MC1R gene and get its coding sequence from 67 Tibetan pigs from different regions of Tibetan Plateau and 128 introducedWhite pigsfrom Denmark to analysis the genetic diversity of MC1R in these two groups, and to build a simple intermediary network together with CDS sequences of MC1Rgene of other breedsdownloaded from public database.We found a nonsynonymous G373A mutation in the first codon position that resulted inamino acid residue replacement (Aspartic acid to Asparagine) in all of the White pigs. We also found a new haplotype in whicha synonymous mutation G93A occurred that causes no amino acid changes.While in Tibetan pigs, two nonsynonymous mutations (G152C, G373A) were found, leading to amino acids changes (Serine to Threonine and Aspartic acid toAsparagine, respectively.) According to the hierarchical diagram and haplotype network diagram, our analysis showed MC1R can be divided into three categories, include Chinese black pigs, European white pigs and Asia wild boar.Each cluster contains a predominant haplotypes, in particular, haplotype Hap-5 in Asian black pig, harboringvarious local pig breeds; haplotype Hap-2, presented mainly byEuropean breeds; haplotype Hap-13, mainly containing Asian wild boar, but other haplotypes still account for a large proportion. This distribution pattern indicates thericher genetic diversity in wild boar than that of domesticated pigs, indicating that MC1R gene in domesticated pigs had underwentstrong artificialselection. Finally, the network analysis confirmed the independent domestication events in Europe and Asia, accompanied by MC1R geneintrogression in Chinese domesticated pigs. Genetic diversity of Tibetan pigs is much richer than that of White pigs introduced from Denmark, indicating that Tibetan pigs has underwent less artificial selection. The distributionpattern ofMC1R gene haplotype in Tibetan pig population indicates that gene flow events were occurred in part of the distribution areas of the Tibetan pigs that lead to lineage contamination. More effort has to be put into carry out the conservation work of Tibetan pigs.However, limited by the complexity of the genotype-phenotype map of coatcolor (other genes are also involved in coat color variation regulation such asKIT, ASIPet al.), we were unable to elucidating the molecular mechanism underlyingcoat color variation simply based on MC1R gene polymorphism. In conclusion, our results indicate that MC1R gene had underwentstrong artificial selection during domestication, and it can be used as a molecular marker for further study. Our study will also benefit to understanding the origins of Tibetan pigs and their unique genetic resources.