Homoploid hybrid speciation in action
Homoploid hybrid speciation in action
复制标题
DOI：
10.1002/tax.595005
复制
发表时间：
2010-10-01
期刊：
影响因子：
3.4
通讯作者：
Brennan, Adrian C.
中科院分区：
文献类型：
--
作者：
Abbott, Richard J.;Hegarty, Matthew J.;Brennan, Adrian C.
同倍体杂种物种形成是指染色体数目不变的杂种物种的起源。虽然目前被认为是一种罕见的物种形成形式，特别是相对于更常见的异源多倍体杂交物种形成，但由于遗传资源很容易用于测试它们的存在，因此未来将发现许多同源多倍体杂交物种的例子。在这篇综述中，我们专注于同倍体杂交物种形成的速度，生态和空间隔离的重要性，在这个过程中，发生在一个新的混合在其起源和建立在野外的遗传变化的性质。本文主要参考向日葵属同倍体杂交种的大量研究工作和我们自己对最近起源的二倍体杂交种千里光（Seneciosqualidus）的研究工作，综述了以下证据：（1）新的可育同倍体杂交种可以很快起源，尽管在该种的基因组和表型完全稳定之前可能需要较长的时间;（2）杂交种与其亲本的生态分化是成功建立的关键，并且即使在没有由染色体和/或遗传不育障碍引起的合子后隔离的情况下也会发生这种分化;（三）表型性状和基因表达的超亲性变化对于同倍体杂种物种适应生态和空间上与之不同的生境具有重要意义。父母的，（4）在亲本基因流动的情况下，将同倍体杂种物种与其亲本物种区分开的适应性差异可能会保持，并且在代表物种的多个起源的群体中协调一致地进化;（5）在没有亲本基因流动的情况下，即，在地理隔离的条件下，由于创始者事件、遗传漂变和选择的综合作用，杂交种的快速遗传分化可能会得到加强。
Homoploid hybrid speciation is the origin of a hybrid species without change in chromosome number. Although currently thought to be a rare form of speciation, especially relative to the more common allopolyploid hybrid speciation, it is feasible that many examples of homoploid hybrid species will be discovered in the future now that genetic resources are readily available for testing their occurrence. In this review, we focus on the speed of homoploid hybrid speciation, the importance of ecological and spatial isolation in the process, and the nature of genetic changes that occur in a new hybrid during its origin and establishment in the wild. With reference mainly to the extensive work carried out on homoploid hybrid species of Helianthus, and to our own work on the very recently originated diploid hybrid species Senecio squalidus, we review evidence showing: (1) that new fertile homoploid hybrid species can originate very quickly, although a longer period is likely to be required before the species becomes fully stabilized both genomically and phenotypically; (2) ecological divergence of the hybrid species from its parents is key to successful establishment, and that this can occur even in the absence of post-zygotic isolation caused by chromosomal and/or genetic sterility barriers; (3) transgressive changes in phenotypic traits and gene expression are of great importance in adapting homoploid hybrid species to habitats that are ecologically and spatially divergent from those of the parents; (4) adaptive differences distinguishing a homoploid hybrid species from its parental species are likely to be maintained in the face of parental gene flow, and evolve in concert across populations representing multiple origins of the species; (5) in the absence of parental gene flow, i.e., under conditions of geographical isolation, rapid genetic divergence of the hybrid species is likely to be enhanced due to the combined effects of founder events, genetic drift and selection.