Distribution of the mutant allele of the DMRT3 gene associated with ambling gaits in Japanese native horse populations.

There are currently eight native horse populations in Japan, namely, Hokkaido, Kiso, Noma, Taishu, Misaki, Tokara, Miyako, and Yonaguni horses. Since locomotion traits, including gaitedness, are important for riding and packing horses, the genetic properties associated with these traits could be informative for understanding the characteristics and history of these horses. In this study, we investigated the distribution of the mutant allele of DMRT3 gene (DMRT3:p.Ser301Ter) associated with ambling gaits in the Japanese native horse. We also examined haplotypes of SNPs in the 83-kb region including DMRT3 gene by genotyping four SNPs in this region. The results revealed the presence of DMRT3:p.Ser301Ter in the Hokkaido and Yonaguni populations at allele frequencies of 0.18 and 0.02, respectively, and the observed haplotype associated with DMRT3:p.Ser301Ter was estimated as the most common haplotype in the horses in the world. Since DMRT3:p.Ser301Ter has been hypothesized to spread across Eurasian continent from Medieval England after 850 to 900 CE, our findings of the presence of DMRT3:p.Ser301Ter with the common haplotype in the Japanese native horses will provide a new insight into the history of the Japanese native horse, such as considerable level of gene flow from Eurasian continent after 850 to 900 CE.