The Genetic Diversity and Phylogenetic Relationships of Five Guangxi Pig Breeds and Three Exotic Pig Breeds by Analysis of mtDNA D-loop Sequences

In order to compare the genetic diversity and phylogenetic relationships between Guangxi pig breeds and three exotic pig breeds,one pair of primers was used to amplify 85 mtDNA D-loop sequences of five Guangxi pig breeds (Bama Xiang pig,Dongshan pig,Guizhong spotted pig,Luchuan pig,Huanjiang Xiang pig),and we downloaded 45 mtDNA D-loop sequences of three exotic pig breeds (Duroc,Yorkshire,Landrace) from GenBank.Then the haplotype,genetic diversity and phylogenetics analysis were carried out.The results showed that 38 haplotypes were identified in 130 sequences,and the mean distances among Guangxi pig breeds were smaller than that among Duroc,Landrace and Guangxi pig breeds.The NJ phylogenetic tree classified all samples into two clusters.One contained all of Guangxi pig breeds and partial Yorkshire,the other was composed wholly of exotic pig breeds,which mean there were two distinct maternal origins.In the cluster of Guangxi pig breeds,Luchuan pig were clustered,and the others were rather dispersive.It indicated that Luchuan pig had simple maternal bloods,and the other breeds had complex maternal bloods,and they had gene flow with each other.The maternal pig resources in Guangxi were not affected by the introduction of exotic pig breeds,and they were still suitable for use as a female parent in their development and utilization.