Genetic diversity of the Yonaguni horse based on polymorphisms inmicrosatellites and mitochondrial DNA

[摘要] Thirty-two microsatellites and a mitochondrial DNA haplotypes of endangered Yonagunihorses were analyzed to establish a pedigree registration system and to understand theirgenetic diversity for planning effective conservation. Blood samples were collected from78 of the 130 horses in existence, and DNA was extracted and genotyped. There were twomajor findings. One is that it is possible to use microsatellites for Yonaguni horsepedigree registration in the future because the power of exclusion of parentage testing isreliable at 0.999998. The second is the clarification of the current genetic diversity ofYonaguni horses. The average number of alleles, observed heterozygosity, expectedheterozygosity and fixation index were 4.4, 0.591, 0.601 and 0.016, respectively, for theanalyzed horses. The probability of a genetic bottleneck, under the assumptions of thestepwise mutation model, was 0.432, suggesting that the genetic structure of the horseswas not influenced by a recent bottleneck. Genetic distance between individuals wasvisualized by a phylogenetic tree based on the proportion of shared alleles. Structureanalysis based on Bayesian clustering revealed the possibility that Yonaguni horsescomprise four or five subpopulations. Consequently, although only two haplotypes wereidentified in the mitochondrial analysis, genetic diversity of Yonaguni horses was notparticularly low in comparison with that of other breeds that are at risk ofextinction.

[学科分类] 兽医学

[关键词] conservation genetics;microsatellite;mitochondrial DNA;Yonaguni horse