Genetic conservation of rare coniferous natural forests in Japan

我们调查了25个自然种群的Chamaaparis obtusa使用51个切割扩增多态性序列（CAPS）标记，这是开发使用的信息序列标记位点（STS）在柳杉。大多数CAPS标记具有共显性表达模式，并且由于其稳健性和方便性而适合于群体研究。我们估计了各种遗传多样性参数，包括平均杂合性（He）和等位基因丰富度，并发现，更外围的人群往往有较低的遗传多样性比中心人群，与以前的理论研究。群体间的总体遗传分化较低，但具有统计学显著性（GST=0.039），与先前等位酶研究中报道的水平相似。我们试图检测与局部适应相关的非中性位点，以阐明每个位点的注视指数（FST）和He值之间的关系，并发现了7个候选非中性位点。 关于我们 tral位点系统发育树分析的人口和贝叶斯聚类分析揭示了一种模式，逐渐增加隔离的人口与地理距离的增加。三个种群有高度的连锁不平衡，我们归因于严重的瓶颈，由于人类干扰或竞争与其他物种在最近的冰川后，他们从避难所迁移。本研究利用148个酶切扩增多态性序列标记对29个柳杉天然居群进行了遗传结构分析，并筛选了该种的适应性基因。根据推断的进化历史的物种在末次冰期和之后的插曲，遗传多样性较高，在西部人口比北方人口。系统发育和遗传结构分析的结果表明，该物种的两个主要品种的人口已明显偏离彼此，和两个被检查的位点是强烈相关的两个品种之间的分化。使用基于FST和He值的聚结模拟，我们检测到五个基因具有高于99%置信区间（CI）的值，两个基因具有低于99%置信区间（CI）的值，99%置信区间（CI）是中性无限岛模型下的理论预期区间。我们还检测到13个离群位点，使用合并模拟的基础上的假设，这两个品种起源于祖先群体的分裂。这两种方法都检测到了其中的四个基因座，其中两个在遗传结构分析中被检测到为与分化相关的基因座，并且是经过选择的基因的强有力候选基因，因此有助于两个基因之间的遗传分化物种的品种。少

We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (He) and allelic richness, and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (GST=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect nonneutral loci associated with local adaptation to clarify the relationship between the fixation index (FST) and He-values for each locus, and found seven candidate nonneu … More tral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We also discuss the importance of these natural populations of C.obtusa as a genetic resource.We investigated 29 natural populations of Cryptomeria japonica using 148 cleaved amplified polymorphic sequence markers to elucidate their genetic structure and identify candidate adaptive genes of this species. In accordance with the inferred evolutionary history of the species during and after the last glacial episode, the genetic diversity was higher in western populations than in northern populations. The results of phylogenetic and genetic structure analyses suggest that populations of the two main varieties of the species have clearly diverged from each other, and that two of the examined loci are strongly associated with the differentiation between the two varieties. Using a coalescent simulation based on FST and He values, we detected five genes that had higher, and two that had lower, values than the respective 99 % confidence intervals (CIs) that are theoretically expected intervals under a neutral infinite-island model. We also detected 13 outlier loci using a coalescent simulation based on the assumption that the two varieties originated from the splitting of an ancestral population. Four of these loci were detected by both methods, two of which were detected in a genetic structure analysis as loci associated with differentiation, and are strong candidates for genes that have been subject to selection and, thus, contributed to the genetic differentiation between the two varieties of the species. Less