Abstract
There are three native pigs found in Okinawa and Amami-Ohshima, namely Aguh, Ayoh and Ohshima-Shimabuta. They are valuable local genetic resources and their meat is highly desirable. Especially, the melting point of the fat is low and delicious. Despite their importance, information concerning genetic background of Okinawa and Amami native pigs is lacking. In this study, we analyzed the mitochondrial DNA D-loop region of Okinawa and Amami native pigs to clarify their genetic background. In total, 18 pig specimens of Aguh, Ayoh and Ohshima-Shimabuta six each were analyzed. Two haplotypes were observed amongst the sampled native pigs, one in Aguh and Ohshima-Shimabuta (Type 1), while other in Ayoh (Type 2). This result suggested that Ayoh has a different genetic background in Okinawa and Amami native pigs. In recent years, population size of those native pigs has considerably reduced. In order to increase their population size and reintegrate their morphological traits, they were crossed with other pig breeds. Aguh and Ohshima-Shimabuta were crossed with European breeds such as Berkshire and Hampshire to improve their meat quality. In the phylogenetic tree constructed with reported D-loop sequences of other breeds of domestic pigs and wild boars, Okinawa and Amami native pigs were clustered with Asian pigs and wild boars. The Asian cluster was further grouped into two subclusters with one containing Ayoh and Japanese wild boars suggesting their close genetic relationships while the remaining subcluster includes Aguh, Ohshima-Shimabuta and European Berkshire and Large White breeds. These results also supported the history of Okinawa and Amami native pigs.
