Senju Natsuko, Tozaki Teruaki, Kakoi Hironaga, Almunia Julio, Maeda Masami, Matsuyama Ryota, Takasu Masaki
Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
J Vet Med Sci. 2017 Jan 24;79(1):218-223. doi: 10.1292/jvms.16-0111. Epub 2016 Oct 28.
To help plan conservation of the endangered Miyako horse, a biological resource of the Miyako Islands in Japan, we characterized the genetics of the breed by genotyping 32 microsatellites and identifying mitochondrial DNA haplotypes. We also calculated genetic distances between individuals based on the proportion of shared alleles and visualized the genetic relationships with a phylogenetic tree. Two important results were obtained. One is that accurate pedigree registration of the horse by using microsatellites is possible, as the exclusion power of parentage testing is 0.999998. Another is that the current genetic diversity of the horses was clarified. The average number of alleles, observed heterozygosity and expected heterozygosity were 4.2, 0.701 and 0.649, respectively, for the 35 analyzed horses. The probability values for bottleneck models (infinite allele model: 0.00000; stepwise mutation model: 0.00026; and two-phase model: 0.00000) suggested that Miyako horses have experienced a recent genetic bottleneck. Only one mitochondrial haplotype was identified. Consequently, genetic diversity within the population is relatively well-maintained despite a very small population size (41 at the time of the study), and the first priority in conservation of the Miyako horse is to increase the population size.
为了帮助规划对濒危的宫古马（日本宫古岛的一种生物资源）的保护工作，我们通过对32个微卫星进行基因分型并鉴定线粒体DNA单倍型，对该品种的遗传学特征进行了分析。我们还根据共享等位基因的比例计算了个体之间的遗传距离，并通过系统发育树直观展示了遗传关系。我们获得了两个重要结果。一是利用微卫星对马进行准确的系谱登记是可行的，因为亲子关系检测的排除能力为0.999998。另一个是明确了当前马匹的遗传多样性。对于35匹被分析的马，等位基因的平均数量、观察到的杂合度和预期杂合度分别为4.2、0.701和0.649。瓶颈模型的概率值（无限等位基因模型：0.00000；逐步突变模型：0.00026；两阶段模型：0.00000）表明宫古马近期经历了遗传瓶颈。仅鉴定出一种线粒体单倍型。因此，尽管种群规模非常小（研究时为41匹），但种群内部的遗传多样性仍得到了较好的维持，宫古马保护工作的首要任务是增加种群规模。
