Molecular ecological study for conservation of endangered species, Pyrus calleryana Decne var. dimorphopheylla (Makino) Koidz. : Genetic analysis on population structure, gene flow and reproductive deterioration

为获得油梨的遗传信息，为油梨的保护提供依据。对日本现存的所有濒危物种Dylopheylla(Makino)Koidz.的个体进行了采样和起源调查，结果表明，它们的总个体数为465只，仅分布在爱知县和三叠县。用10个核SSR标记对它们进行了基因分型。该物种保持了遗传多样性，然而，在所有包含受严重人类影响(如种植和移植)影响的种群中，“距离隔离”的模式并不明显。相比之下，本地种群的遗传结构是保守的。系统发育树和贝叶斯聚类分析表明，原住民群体可分为两大类群，分别为爱知和米氏。分析与自交不亲和基因座的等位基因对应的cDNA的核苷酸序列，发现了11个不同的等位基因。利用针对S等位基因设计的特异性引物，对10个群体的2 47个个体进行了S基因分型，结果表明，每个群体有4~10个S等位基因。利用9个SSR标记对分离群体中4株母树的种子进行父本分析，结果表明花粉亲本在群体中分布广泛。用广义线性混合模型(GLMM)对影响雄性贡献的生态和遗传因素进行了分析，结果表明，与母亲的距离是影响雄性繁殖成功的最显著因素。虽然自交不亲和性在种群内的交配事件中起作用，但亲本间的S基因同一性程度并不强烈地影响花粉介导的基因扩散，这些结果将为该物种的保护规划提供重要信息。

In order to obtain genetic information for conservation of Pyrus calleryana Decne var. dimorphopheylla (Makino) Koidz., the endangered species, all of the individuals exist in Japan were sampled and inquired their origin, revealed that total number of individuals is 465 and they distributed only in Aich and Mie Prefecture. Genotypes of them were determined with ten nuclear SSR markers. Genetic diversity was maintained in this species, however, patterns of "isolation by distance" was not clear among all populations containing those affected by serious human impacts, such as, planting and transplanting. In contrast, genetic structure among the native populations was conserved. Phylogenetic tree and Bayesian cluster analysis revealed that the native populations were divided into two clusters, those are Aichi and Mie. Analyzing the nucleotide sequences for cDNAs corresponding to the alleles of the self-incompatible locus revealed eleven different alleles. Using the specific primers designed for each of S-allele, S-genotypes for 247 individuals collected from ten populations were determined and revealed that four to ten S-alleles were maintained in each population. Paternal analysis for seeds collected from four mother trees in the isolated population was performed with nine SSR markers and revealed that pollen parents were widely distributed in the population. Ecological and genetic factors which affect male contribution was analyzed with generalized linear mixed model (GLMM) and revealed that distance from the mother is the most significant factor for male reproductive success. Although self-incompatibility was functioned in the mating event within the population, degree of S-genotype identity between parents did not strongly affect pollen mediated gene dispersal.These results will provide important information for planning conservation programs of this species.