The likelihood of homoploid hybrid speciation
The likelihood of homoploid hybrid speciation
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DOI：
10.1046/j.1365-2540.2000.00680.x
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发表时间：
2000-04-01
期刊：
影响因子：
3.8
通讯作者：
Rieseberg, LH
中科院分区：
文献类型：
--
作者：
Buerkle, CA;Morris, RJ;Rieseberg, LH
通过杂交可以形成新的物种，而不会增加倍性。对于杂交衍生品来说，面临的挑战是逃避来自亲本物种的基因流的同质化效应。假设这一过程背后的机制是使用计算机模拟来模拟的。这种模式是重组物种形成的，其中亲本物种之间的染色体重排导致F-1杂种育性较差，但通过重组，形成新的纯合类型，从而恢复了育性。在模拟中，携带重组核型的稳定群体频繁产生，并在F-1杂种育性较高时维持。然而，这种高起始率被较低的遗传隔离所抵消，较低的F-1杂种育性增加了派生群体的进化独立性。此外，模拟表明，需要生态和空间隔离才能实现对初生物种的实质性生殖隔离。在该模型中，生态隔离的机会是由于适应了未被亲本物种占据的极端生境而产生的，而任何形式的空间隔离(例如创始人事件)都有助于遗传隔离。我们的结果证实了语言模型中强调的因素组合的重要性，并说明了杂交物种出现的频率和初始物种的遗传完整性之间的权衡。
New species may be formed through hybridization and without an increase in ploidy. The challenge is for hybrid derivatives to escape the homogenizing effects of gene flow from parental species. The mechanisms hypothesized to underlie this process were modelled using a computer simulation. The model is of recombinational speciation, in which chromosomal rearrangements between parental species result in poor fertility of F-1 hybrids, but through recombination, novel homozygous types are formed that have restored fertility. In simulations, stable populations bearing the recombinant karyotypes originated frequently and were maintained when the fertility of F-1 hybrids was high. However, this high rate of origination was offset by low genetic isolation, and lower F-1 hybrid fertility increased the evolutionary independence of derived populations. In addition, simulations showed that ecological and spatial isolation were required to achieve substantial reproductive isolation of incipient species. In the model, the opportunity for ecological isolation arose as a result of adaptation to extreme habitats not occupied by parental species, and any form of spatial isolation (e.g. founder events) contributed to genetic isolation. Our results confirmed the importance of the combination of factors that had been emphasized in verbal models and illustrate the trade-off between the frequency at which hybrid species arise and the genetic integrity of incipient species.