Transgressive segregation in mating traits drives hybrid speciation
Transgressive segregation in mating traits drives hybrid speciation
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DOI：
10.1093/evolut/qpad072
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发表时间：
2023-04-24
期刊：
影响因子：
3.3
通讯作者：
Seehausen，Ole
中科院分区：
文献类型：
--
作者：
Kagawa，Kotaro;Takimoto，Gaku;Seehausen，Ole
杂交可以迅速产生新的遗传变异，这可以通过创造新的适应表型来促进生态物种的形成。然而，产生新的交配表型(如交配季节、生殖器形状、性表现、配偶偏好)的杂交如何影响物种形成仍不清楚，特别是当这些表型不赋予适应优势时。在这里，基于基于个体的进化模拟，我们提出交配特征的超越性分离可以驱动早期的杂交物种形成。模拟表明，当杂交种群受到来自双亲血统的适度持续迁徙时，早期杂交物种形成最频繁，导致杂交的反复发作。轮回杂交不断产生遗传变异，促进了杂交群体中交配表型的快速随机进化。随机进化继续进行，直到一种新的交配表型开始主导杂交群体，这将杂交群体从亲本谱系中繁殖地分离出来。然而，过于频繁的杂交反而阻碍了生殖隔离的进化，因为它夸大了交配表型的变异，产生了允许与亲本交配的表型。模拟还揭示了杂交物种在其初期出现后长期持续存在的条件。我们的结果表明，交配表型的反复超越性分离可以为杂交物种形成和辐射提供一个合理的解释，这些杂交物种和辐射几乎不涉及适应性生态分歧。
Hybridization can rapidly generate novel genetic variation, which can promote ecological speciation by creating novel adaptive phenotypes. However, it remains unclear how hybridization, creating novel mating phenotypes (e.g., mating season, genitalia shapes, sexual displays, mate preferences), affects speciation especially when the phenotypes do not confer adaptive advantages. Here, based on individual-based evolutionary simulations, we propose that transgressive segregation of mating traits can drive incipient hybrid speciation. Simulations demonstrated that incipient hybrid speciation occurred most frequently when the hybrid population received moderate continued immigration from parental lineages causing recurrent episodes of hybridization. Recurrent hybridization constantly generated genetic variation, which promoted the rapid stochastic evolution of mating phenotypes in a hybrid population. The stochastic evolution continued until a novel mating phenotype came to dominate the hybrid population, which reproductively isolates the hybrid population from parental lineages. However, too frequent hybridization rather hindered the evolution of reproductive isolation by inflating the variation of mating phenotypes to produce phenotypes allowing mating with parental lineages. Simulations also revealed conditions for the long-term persistence of hybrid species after their incipient emergence. Our results suggest that recurrent transgressive segregation of mating phenotypes can offer a plausible explanation for hybrid speciation and radiations that involved little adaptive ecological divergence.