Plant speciation across environmental gradients and the occurrence and nature of hybrid zones
Plant speciation across environmental gradients and the occurrence and nature of hybrid zones
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DOI：
10.1111/jse.12267
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发表时间：
2017-07-01
影响因子：
3.7
通讯作者：
Abbott, Richard J.
中科院分区：
文献类型：
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作者：
Abbott, Richard J.
环境梯度是非常普遍的，许多植物物种通过适应性遗传变化来应对环境梯度。这可能是连续变化的第一步，最终导致完全生殖隔离形式的起源，即“生物物种”。在实现完全的生殖隔离之前，不同谱系之间可能通过初级整合或次级接触形成杂交区。本文综述了国内外有关植物杂交带的文献，重点阐述了植物杂交带的起源模式（原生整合与次生接触）；植物科、属和生命形式的分布；亲本系间与强度和生殖隔离类型相关的型和基因型组成；合子前和合子后生殖障碍的性质基因流动的水平和方向；以及混合区在气候变化面前的稳定性。在文献检索中发现的植物杂交带总数少得惊人（137个）。即使在世界上对植物进化、生态学和系统学有着悠久研究历史的地区，情况也是如此。对其原因进行了讨论，包括植物杂交带在野生环境中自然稀少的可能性。只有少数混合带试图区分地层是由初级整合还是次生接触形成的，并且假定大多数混合带起源于次生接触。从现有的有限信息来看，植物杂交带可能会因气候变化而频繁移动，但需要长期研究来证实这一点。
Environmental gradients are very common and many plant species respond to them through adaptive genetic change. This can be a first step along a continuum of change that leads ultimately to the origin of fully reproductively isolated forms, i.e., "biological species'. Before complete reproductive isolation is achieved, hybrid zones may form between divergent lineages either through primary intergradation or secondary contact. Here, I review the literature on plant hybrid zones between native species and highlight: mode of origin (primary intergradation versus secondary contact); distribution among plant families, genera and life form; type and genotypic composition related to strength and type of reproductive isolation between parental lineages; nature of prezygotic and postzygotic reproductive barriers; level and direction of gene flow; and the stability of hybrid zones in the face of climate change. The total number of plant hybrid zones detected in a literature search was surprisingly small (137). This was the case even for areas of the world with a long history of research into plant evolution, ecology and systematics. Reasons for this are discussed, including the possibility that plant hybrid zones are naturally rare in the wild. Only for a few hybrid zones have attempts been made to distinguish between formation by primary intergradation or secondary contact, and it is assumed that most hybrid zones originate through secondary contact. From the limited information available, it appears that plant hybrid zones may frequently move in response to climate change, but long-term studies are required to confirm this.