Mitochondrial DNA-based genetic structure analysis of Pudong White pigs.

There are extensive debates concerning the origin and the necessity of conservation of Pudong White pigs in the Taihu region of China. To elucidate their genetic ancestry, we sequenced the complete mtDNA D-loop sequences of 25 Pudong White pigs and 9 Shawutou pigs from the Taihu region and reanalyzed 158 published sequences of other breeds in GenBank. Haplotypes of all pigs were classified into two clades, A and E, but Pudong White pigs were found only in clade A. The results of population differentiation demonstrated that there were few genetic exchanges among the eight populations. Furthermore, divergence time estimates suggested that the Pudong White pigs split from four types of Taihu pigs at about 0.26-0.75 million years ago. Overall, the results suggest that the Pudong White pig is a unique population, and conservation practice should concentrate on preserving this isolated population.