2018 Volume 55 Issue 1 Pages 12-20
Ryukyu pigs are derived from Chinese pigs, and there are black colored Aguh pigs and Ayoh pigs with white spots. Ryukyu pigs are reported to have been improved by crossing them with Berkshire pigs, but the molecular genetic relationship among Ryukyu pigs, Western pigs, and Chinese pigs remains unclear. Therefore, in order to clarify the genetic relationships, the genotype of the microsatellite 30 loci of AG (B), AG (R), AG (W), their mixed group AG (O), and also their ancestral groups AG06 and AY06 of Nakijin Aguh pigs were used to analyze the genetic diversity of Ryukyu pigs and their genetic structure and relationship with Western and Chinese pigs. Genetic diversity indices, such as the number of effective alleles, allelic richness, and polymorphic information content were smallest for AG (W) and greatest for AG (O). The diversity of AG (O) was comparable to that of Western pigs. In the Nakijin Aguh lines, the observed heterozygosity value tended to be greater than the expected value compared with that of Western pigs, and FIS showed a negative value suggesting that mating to avoid inbreeding was performed. Principal coordinate analysis revealed that Ryukyu pigs, Chinese pigs, and Western pigs formed respective clusters on two dimensions. AG (B) was closely related to AG06, and AG (W) was closely related to AY06 on the phylogenetic tree based on genetic distance, and Ryukyu pigs formed a clade with Chinese pigs. The analysis of genetic structure also revealed that Ryukyu pigs shared a common ancestry with Chinese pigs, but AG (B) and AG (R) had genes derived from a common ancestral group with Berkshire pigs. This result confirms the origin of Ryukyu pigs.
