A genetically explicit model of speciation by sensory drive within a continuous population in aquatic environments
A genetically explicit model of speciation by sensory drive within a continuous population in aquatic environments
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DOI：
10.1186/1471-2148-7-99
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发表时间：
2007-06-28
影响因子：
3.4
通讯作者：
Seehausen, Ole
中科院分区：
文献类型：
--
作者：
Kawata, Masakado;Shoji, Ayako;Seehausen, Ole
背景：感觉驱动假说预测，不同栖息地的不同感觉适应可能导致种群二次接触时的交配前隔离。传统上，感觉驱动的物种形成被视为物种形成的特例，是地理上孤立的种群适应不同环境的副产品。然而，如果栖息地是异质的，感觉系统的局部适应可能会导致来自单一非结构化种群的生殖隔离物种的出现。在多色鱼类中，视觉敏感性可能会适应当地的环境光状况，并且敏感性可能会影响雌性对雄性婚姻颜色的偏好。在本文中，我们研究了通过感觉驱动形成物种的可能性，作为单个最初非结构化群体中不同视觉适应的副产品。我们使用基于显式遗传机制的模型来进行色觉和婚姻着色。结果：我们表明，在对视觉色素和颜色感知的适应性进化进行显式建模的模拟中，感觉驱动可以在连续的栖息地和种群内沿着短选择梯度促进物种形成。我们假设颜色感知会进化以适应个体经历的模态光环境，并且雌性更喜欢与对结婚颜色最敏感的雄性交配。在我们的模拟中，颜色感知取决于个体视觉色素的吸收光谱。当环境光梯度陡度为中等且后代的扩散距离相对较小时，物种形成最常发生。此外，我们的结果预测，导致峰值吸收波长大幅变化的突变会促进物种形成，而当峰值吸收通过影响较小的逐步突变演化时，我们没有观察到物种形成。结论：结果表明，当环境梯度对用于配偶选择的感觉方式产生不同选择时，就会发生物种形成。这种梯度的证据来自几个动物群体，特别是淡水和海洋鱼类。在这种条件下，连续种群中物种形成的概率可能主要取决于感知适应和雌性配偶选择的遗传结构。
Background: The sensory drive hypothesis predicts that divergent sensory adaptation in different habitats may lead to premating isolation upon secondary contact of populations. Speciation by sensory drive has traditionally been treated as a special case of speciation as a byproduct of adaptation to divergent environments in geographically isolated populations. However, if habitats are heterogeneous, local adaptation in the sensory systems may cause the emergence of reproductively isolated species from a single unstructured population. In polychromatic fishes, visual sensitivity might become adapted to local ambient light regimes and the sensitivity might influence female preferences for male nuptial color. In this paper, we investigate the possibility of speciation by sensory drive as a byproduct of divergent visual adaptation within a single initially unstructured population. We use models based on explicit genetic mechanisms for color vision and nuptial coloration.Results: We show that in simulations in which the adaptive evolution of visual pigments and color perception are explicitly modeled, sensory drive can promote speciation along a short selection gradient within a continuous habitat and population. We assumed that color perception evolves to adapt to the modal light environment that individuals experience and that females prefer to mate with males whose nuptial color they are most sensitive to. In our simulations color perception depends on the absorption spectra of an individual's visual pigments. Speciation occurred most frequently when the steepness of the environmental light gradient was intermediate and dispersal distance of offspring was relatively small. In addition, our results predict that mutations that cause large shifts in the wavelength of peak absorption promote speciation, whereas we did not observe speciation when peak absorption evolved by stepwise mutations with small effect.Conclusion: The results suggest that speciation can occur where environmental gradients create divergent selection on sensory modalities that are used in mate choice. Evidence for such gradients exists from several animal groups, and from freshwater and marine fishes in particular. The probability of speciation in a continuous population under such conditions may then critically depend on the genetic architecture of perceptual adaptation and female mate choice.