High population differentiation and unusual haplotype structure in a shade‐intolerant pioneer tree species, Zanthoxylum ailanthoides (Rutaceae) revealed by analysis of DNA polymorphism at four nuclear loci
High population differentiation and unusual haplotype structure in a shade‐intolerant pioneer tree species, Zanthoxylum ailanthoides (Rutaceae) revealed by analysis of DNA polymorphism at four nuclear loci
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DOI：
10.1111/j.1365-294x.2008.03756.x
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发表时间：
2008-05
影响因子：
4.9
通讯作者：
Koichi Kamiya;Etsuko Moritsuka;T. Yoshida;T. Yahara;H. Tachida
中科院分区：
文献类型：
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作者：
Koichi Kamiya;Etsuko Moritsuka;T. Yoshida;T. Yahara;H. Tachida
人口史、生活史特征和繁育系统的差异会影响核苷酸变异模式。预计耐荫先锋树种的遗传多态和种群结构与顶极树种不同。本文研究了东亚暖温带林隙中不耐荫的先锋树种花椒4个淀粉途径基因座(agpSA、agpSB、agpL和GBSSI)的核苷酸多态模式。种群内的遗传多样性低于种群间的遗传多样性，种群间的分化程度较高(FST=0.32-0.64)，这与昆虫传粉繁育系统和该先锋物种的集合种群结构相一致。单倍型的数量比观察到的分离位点的数量要少。单个单倍型占各自座位上所有样本基因的47%以上。这些变异模式与对有限岛模型种群的中性预测不相容。这种先锋树种在历史上复杂的种群动态，如瓶颈和/或混合，可能导致了所观察到的遗传变异和种群结构的格局，这与顶端风媒树种(如针叶树)不同。与本研究中所研究的其他基因座相比，agpL在花椒中几乎没有变异(只有一个独生体)，但在与之密切相关的物种中有一定程度的变异。这表明可能是最近一次选择性扫描在斑潜蝇的位置或其附近。
Differences in demographic history, life‐history traits, and breeding systems affect nucleotide variation patterns. It is expected that shade‐intolerant pioneer tree species have different patterns of genetic polymorphism and population structure than climax species. We studied patterns of nucleotide polymorphism at four putative starch pathway loci (agpSA, agpSB, agpL, and GBSSI) in Zanthoxylum ailanthoides, a shade‐intolerant pioneer tree species that occupies forest gaps in warm‐temperate forests of East Asia. Genetic diversity was lower within each population than among populations, and differentiation among populations was high across the loci (FST = 0.32–0.64), as expected from the insect‐pollinated breeding system and the metapopulation structure of this pioneer species. Numbers of haplotypes were smaller than those expected from the observed numbers of segregating sites. Single haplotypes accounted for more than 47% of all the sampled genes at the respective loci. These variation patterns were incompatible with neutral predictions for populations of a finite island model. Complex population dynamics, such as bottleneck and/or admixture, in the history of this pioneer tree species might have resulted in the observed patterns of genetic variation and population structure, which are different from those of climax wind‐pollinated tree species, such as conifers. In contrast to the other loci investigated in this study, agpL showed nearly no variation in Z. ailanthoides (one singleton only), but there was some extent of variation in a closely related species, Zanthoxylum schinifolium. This suggests possibly a recent selective sweep at or near the locus in Z. ailanthoides.