Wide‐range analysis of genetic structure of Betula maximowicziana, a long‐lived pioneer tree species and noble hardwood in the cool temperate zone of Japan
Wide‐range analysis of genetic structure of Betula maximowicziana, a long‐lived pioneer tree species and noble hardwood in the cool temperate zone of Japan
复制标题
DOI：
10.1111/j.1365-294x.2005.02715.x
复制
发表时间：
2005-11
影响因子：
4.9
通讯作者：
Y. Tsuda;Yuji Ide
中科院分区：
文献类型：
--
作者：
Y. Tsuda;Yuji Ide
大桦是日本冷温带森林中寿命较长的先锋树种，在维持森林生态系统方面发挥着重要作用，具有很高的经济价值。在这里，我们评估了B的23个自然群体的广泛遗传结构。maximowicziana 11个简单重复序列（SSR）位点。所有群体的遗传多样性相对较低（平均HE，0.361;平均等位基因丰富度，2.80;平均稀有等位基因丰富度，1.02）。种群分化也相对较低（FST，0.062）。基于遗传距离和贝叶斯聚类分析表明，这里研究的群体可以分为一个南方组和一个北方组。罕见的等位基因的丰富性和贝叶斯聚类分析揭示了在末次冰期南部和北方避难所的证据。此外，区域遗传多样性的比较显示显着的等位基因丰富度的渐变。在空间遗传结构评价中，23个居群间存在显著的距离隔离（IBD），但在区域内不存在。此外，在无限等位基因模型（IAM）的假设下，在所有群体中发现了显着的人口瓶颈。这些不寻常的，重要的瓶颈可能是因为冰后期殖民化的过程和物种的特性和/或生活史作为一个长寿的先驱树种。本研究中发现的广泛的区域遗传结构为保护和森林管理提供了重要的基线，包括识别B的进化重要单位（ESU）和/或管理单位（MU）。maximowicziana。
Betula maximowicziana is a long‐lived pioneer tree species in Japanese cool temperate forests that plays an important role in maintenance of the forest ecosystem and has high economic value. Here we assess the wide‐range genetic structure of 23 natural populations of B. maximowicziana using 11 simple sequence repeat (SSR) loci. Genetic diversity within populations was relatively low in all populations (mean HE, 0.361; mean allelic richness, 2.80; mean rare allelic richness, 1.02). The population differentiation was also relatively low (FST, 0.062). Genetic distance‐based and Bayesian clustering analysis revealed that the populations examined here could be divided into a southern group and a northern group. Analysis of rare allelic richness and Bayesian clustering revealed evidence for both southern and northern refugia during the last glacial period. Furthermore, a comparison of regional genetic diversity revealed significant clines in allelic richness. In spatial genetic structure evaluation, significant isolation by distance (IBD) was detected among the 23 populations, but not within regions. Moreover, significant population bottlenecks were found in all populations under infinite allele model (IAM) assumptions. These unusual, significant bottlenecks might be because of the processes of postglacial colonization and the species’ characters and/or life history as a long‐lived pioneer tree species. The wide‐range, regional genetic structure found in this study provides an important baseline for conservation and forest management, including the identification of evolutionarily significant units (ESUs) and/or management units (MUs) of B. maximowicziana.