Effect of gene flow on spatial genetic structure in the riparian canopy tree Cercidiphyllum japonicum revealed by microsatellite analysis
Effect of gene flow on spatial genetic structure in the riparian canopy tree Cercidiphyllum japonicum revealed by microsatellite analysis
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DOI：
10.1038/sj.hdy.6800748
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发表时间：
2006
期刊：
影响因子：
3.8
通讯作者：
T. Sato;Yuji Isagi;H. Sakio;K. Osumi;Susumu Goto
中科院分区：
文献类型：
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作者：
T. Sato;Yuji Isagi;H. Sakio;K. Osumi;Susumu Goto
很少有研究分析局部范围内的花粉和种子运动，以及涵盖物种地理分布范围的种群之间的遗传分化。我们对连香树进行了这样的研究；日本寒温带河岸森林的雌雄异株阔叶树。我们直接测量了某个地点的花粉和种子运动、当地规模的遗传结构以及覆盖日本群岛的种群之间的遗传分化。对 20 公顷研究地点内幼苗的亲子关系分析表明，至少 28.8% 的幼苗是通过研究地点外树木的花粉受精的。研究地点内的平均授粉距离为129 m，最大为666 m。 30%的幼苗与最近的母树基因型不相容，研究地点内种子最大传播距离超过300 m。因此，长距离基因传播在该物种中很常见。种群内成年树木的遗传相关性和空间距离之间的相关性并不显着，表明精细遗传结构的缺失可能是由高水平的花粉流和重叠的种子阴影引起的。在日本日本刺参分布范围内采样的 6 个种群表现出显着的距离隔离，但遗传分化水平较低 (F ST= 0.043)，也表明刺参中存在长距离基因流动。长距离基因流动对不同空间尺度的遗传结构产生强烈影响，有助于维持日本刺参遗传多样性。
Few studies have analyzed pollen and seed movements at local scale, and genetic differentiation among populations covering the geographic distribution range of a species. We carried out such a study on Cercidiphyllum japonicum; a dioecious broad-leaved tree of cool-temperate riparian forest in Japan. We made direct measurement of pollen and seed movements in a site, genetic structure at the local scale, and genetic differentiation between populations covering the Japanese Archipelago. Parentage analysis of seedlings within a 20-ha study site indicated that at least 28.8% of seedlings were fertilized by pollen from trees outside the study site. The average pollination distance within the study site was 129 m, with a maximum of 666 m. The genotypes of 30% of seedlings were incompatible with those of the nearest female tree, and the maximum seed dispersal distance within the study site was over 300 m. Thus, long-distance gene dispersal is common in this species. The correlation between genetic relatedness and spatial distance among adult trees within the population was not significant, indicating an absence of fine-scale genetic structure perhaps caused by high levels of pollen flow and overlapping seed shadows. Six populations sampled throughout the distribution of C. japonicum in Japan showed significant isolation-by-distance but low levels of genetic differentiation (F ST= 0.043), also indicating long-distance gene flow in C. japonicum. Long-distance gene flow had a strong influence on the genetic structure at different spatial scales, and contributes to the maintenance of genetic diversity in C. japonicum.