Population structure of Vietnamese pigs using mitochondrial DNA.

The D-loop region on mitochondrial DNA (mtDNA) is frequently used for analyses of maternal lineages within domestic animal species. There are many native pig breeds in Vietnam, but their origins remain unclear. This study investigated maternal lineages using the D-loop region on mtDNA of 260 samples collected from native pigs in 20 provinces across Vietnam. The D-loop region of all samples was amplified and sequenced. We obtained 713 bp sequences of the D-loop region for each sample excluding the repeat region, and variants on this region were used to construct a phylogenetic tree. We detected 50 haplotypes from Vietnamese native pigs, with 27 novel haplotypes. Phylogenetic tree analysis showed two haplotype groups: one for the MTSEA group, frequently found in domestic pigs in the mountainous areas of Cambodia and Laos; and the D2 group, found in pigs originating from Chinese pigs. No European haplotype was found. Haplotypes in northeast Vietnam comprised only haplotypes of the D2 group, whereas in areas from the northwest mountains to the south, we found haplotypes belonging to both the D2 and MTSEA groups. This study suggested that both origins contributed to maternal lineages of current populations of Vietnamese native pigs.

Evaluation of genetic richness among Vietnamese native pig breeds using microsatellite markers.

We have elucidated genetic relationships of Vietnamese native pigs (VNP) using preliminarily collected samples by a single-nucleotide polymorphism (SNP) array. In order to confirm our previous results and compare with the results of a previous study using microsatellite (MS) markers, we aimed to characterize genetic diversity and population structure in wider varieties (24 breeds from 21 Provinces) of VNP across the country using 20 polymorphic MS markers recommended by ISAG/FAO (International Society for Animal Genetics/Food and Agriculture Organization) for diversity study. In this study, we collected 1,136 DNA samples of the VNPs and three exotic breeds. Our results revealed that the average number of alleles and allelic richness across the loci in VNPs were 10.0 and 7.6, which were higher than those of exotic breeds. Genomic components among VNPs were subjected to the sampling locations. Interestingly, Co Binh Thuan showed remarkable genetic feature compared to the other VNPs, because the habitation of Co Binh Thuan was relatively far from the other breeds. The results of this study provided useful information for exploitation, conservation, and development trends of the VNP breeds. More recently, African swine fever caused significant damage to most of the VNP populations. Therefore, our findings will help a reconstruction scheme of the VNP genetic resources.