We investigated whether regular changes of the sire in a breeding farm of Hokkaido Native Horses (HKDs) enables the DNA-level genetic variation of the produced animals to be maintained. The genotypes of 31 microsatellite markers were identified and analyzed in 207 animals produced in a breeding farm in which the sire was replaced every 3 to 5 years. The mean allele number indicating the degree of genetic variation was 5.97 and was similar to those reported previously. The mean observed heterozygosity was 0.74 and was higher than the expected heterozygosity, 0.69; FIS was -0.07, indicating that the analyzed animals reflected frequent outbreeding and had maintained genetic variation. Based on genetic structural analysis, the number of genetic subpopulations of the animals was estimated to be as 6, and the majority (more than 50%) of each subpopulation corresponded to the progeny of one of the sires used in the breeding farm; these observations suggested that genetic variation in the analyzed animals reflected the genetic differences among sires. Pedigree records indicated that the average co-ancestry coefficient between sires used in the breeding farm was 0.015 corresponding to second cousin. This level of kinship among sires is acceptable for producing HKDs that maintain genetic variation.

中文翻译：

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育种场中种公的变化可以维持北海道本地马群的 DNA 水平遗传变异。

我们调查了北海道本地马 (HKDs) 育种场中父亲的定期变化是否能够维持所生产动物的 DNA 水平遗传变异。对每 3 至 5 年更换一次父本的育种场生产的 207 头动物的 31 种微卫星标记的基因型进行了鉴定和分析。指示遗传变异程度的平均等位基因数为 5.97，与先前报道的相似。观察到的平均杂合性为 0.74，高于预期的杂合性 0.69；FIS 为 -0.07，表明所分析的动物反映了频繁的远系繁殖并保持了遗传变异。根据遗传结构分析，动物的遗传亚群数量估计为6，每个亚群的大多数（超过 50%）对应于育种场中使用的其中一头公牛的后代；这些观察结果表明，所分析动物的遗传变异反映了父系之间的遗传差异。系谱记录表明，育种场中使用的父系之间的平均共同祖先系数为 0.015，对应于第二代表亲。种公之间的这种亲缘关系水平对于生产保持遗传变异的 HKD 是可以接受的。