Niche conservatism promotes speciation in cycads: the case of Dioon merolae (Zamiaceae) in Mexico
Niche conservatism promotes speciation in cycads: the case of Dioon merolae (Zamiaceae) in Mexico
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DOI：
10.1111/nph.16647
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发表时间：
2020-06-03
期刊：
影响因子：
9.4
通讯作者：
Murakami, Masashi
中科院分区：
文献类型：
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作者：
Gutierrez-Ortega, Jose Said;Magdalena Salinas-Rodriguez, Maria;Murakami, Masashi
利基保守主义是指血统保留与其祖先相同的利基的倾向。它限制生物群体并防止生态分化。然而，理论预测生态位保守主义可以阻碍基因流动、加强漂移并增加局部适应：这是否意味着它也可以促进物种形成？为什么会出现这种情况？我们旨在回答这些问题。我们检查了 Dioon merolae 苏铁种群的叶绿体 DNA 变异、全基因组单核苷酸多态性、形态特征和环境变量。我们测试了地理结构、人口历史情景以及种群之间的生态位保守主义。谱系分歧与由不适合苏铁植物栖息地组成的地理屏障的存在有关。地理群体之间存在明显的遗传和形态差异，表明异域分化。然而，即使在对比现有的环境条件下，群体仍保留其祖先的生态位，支持生态位保守主义。生态位保守主义是一个可以促进物种形成的过程。在 D. merolae 中，发生谱系分歧是因为不合适的栖息地代表了基因流动的障碍，导致种群经历孤立的人口历史和不同的环境条件。这项研究解释了为什么苏铁植物尽管具有古老的谱系起源和生物停滞，却能够多样化进入世界范围内的现代生态系统。
Niche conservatism is the tendency of lineages to retain the same niche as their ancestors. It constrains biological groups and prevents ecological divergence. However, theory predicts that niche conservatism can hinder gene flow, strengthen drift and increase local adaptation: does it mean that it also can facilitate speciation? Why does this happen? We aim to answer these questions.We examined the variation of chloroplast DNA, genome-wide single nucleotide polymorphisms, morphological traits and environmental variables across the Dioon merolae cycad populations. We tested geographical structure, scenarios of demographic history, and niche conservatism between population groups.Lineage divergence is associated with the presence of a geographical barrier consisting of unsuitable habitats for cycads. There is a clear genetic and morphological distinction between the geographical groups, suggesting allopatric divergence. However, even in contrasting available environmental conditions, groups retain their ancestral niche, supporting niche conservatism.Niche conservatism is a process that can promote speciation. In D. merolae, lineage divergence occurred because unsuitable habitats represented a barrier against gene flow, incurring populations to experience isolated demographic histories and disparate environmental conditions. This study explains why cycads, despite their ancient lineage origin and biological stasis, have been able to diversify into modern ecosystems worldwide.