Alexander H J, Breden F
Department of Biological Sciences, Simon Fraser University, Burnaby, Canada.
J Evol Biol. 2004 Nov;17(6):1238-54. doi: 10.1111/j.1420-9101.2004.00788.x.
Theory predicts that sexual selection can promote the evolution of reproductive isolation and speciation. Those cases in which sexual selection has led to speciation should be characterized by significant differentiation in male display traits and correlated female preferences in the absence of post-zygotic isolation, accompanied by little genetic or other morphological differentiation. Previous evidence indicates that a cluster of populations of the guppy (Poecilia reticulata Peters) from Cumana, Venezuela, the 'Cumana guppy', differs significantly in female preferences from a nearby guppy population (A. Lindholm & F. Breden, Am. Nat., 160: 2002, S214). Here, we further document sexual isolation between these populations. In addition, these populations exhibit significant divergence in male display traits correlated to differences in between-population mating success, little mitochondrial genetic differentiation, and we find no evidence for genetic incompatibility between a Cumana population and several geographically isolated populations. These results suggest that divergent sexual selection has contributed to differentiation of the Cumana guppy, and this may be the first example of incipient speciation in the guppy.
理论预测，性选择能够推动生殖隔离和物种形成的进化。在性选择导致物种形成的案例中，其特征应表现为雄性展示性状存在显著差异，且雌性偏好与之相关，同时不存在合子后隔离，并且几乎没有遗传或其他形态学上的差异。先前的证据表明，来自委内瑞拉库马纳的一群孔雀鱼（Poecilia reticulata Peters），即“库马纳孔雀鱼”，与附近的孔雀鱼种群相比，雌性偏好存在显著差异（A. 林德霍尔姆和F. 布雷登，《美国博物学家》，160: 2002, S214）。在此，我们进一步记录了这些种群之间的性隔离。此外，这些种群在与种群间交配成功率差异相关的雄性展示性状上表现出显著分歧，线粒体遗传差异极小，而且我们没有发现库马纳种群与几个地理隔离种群之间存在遗传不相容的证据。这些结果表明，分歧性选择促成了库马纳孔雀鱼的分化，这可能是孔雀鱼初始物种形成的首个实例。
