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Summary Previously, a single nucleotide polymorphism ( SNP ) related to gait type was identified at position 22 999 655 of chromosome 23 in the coding region of DMRT 3 ( DMRT 3:Ser301Ter) by showing that a cytosine (C) to adenine (A) mutation of this SNP induced pace in the Icelandic horse. We investigated the effect of DMRT 3:Ser301Ter on the gait of Hokkaido Native Horses, a Japanese native breed, and examined genetic factors other than DMRT 3 by exploring genome‐wide SNP s related to gait determination. All animals exhibiting pace were AA for DMRT 3:Ser301Ter, confirming the association of DMRT 3:Ser301Ter with gait determination; however, 14.3% of the animals exhibiting trot also had AA for DMRT 3:Ser301Ter, suggesting the presence of another factor(s) cooperatively working with DMRT 3:Ser301Ter for gait determination. SNP s on chromosomes 13 and 23 were detected by genome‐wide association analysis (false discovery rate <0.05), although SNP s on chromosome 23 were all located in the vicinity of DMRT 3:Ser301Ter, confirming the association with DMRT 3 . A genome‐wide association study targeting only animals with AA for DMRT 3:Ser301Ter to examine genetic factors cooperatively working with DMRT 3:Ser301Ter for gait determination suggested associations of 23 SNP s on six chromosomes. In a series of analyses of the effect of a maternal factor (dam's gait) on gait determination, the effect was suggested in comparison of the frequencies of exhibiting pace in gait checks in only two animal groups having dams with different DMRT 3:Ser301Ter genotypes ( P < 0.05), suggesting that the gait of the dam does not have a major effect on whether progeny homozygous for the DMRT 3:Ser301Ter mutation will preferentially pace or trot.
Amano et al. (Tue,) studied this question.