Shaw Kerry L, Lesnick Sky C
Department of Biology, University of Maryland, College Park, MD 20742, USA.
Proc Natl Acad Sci U S A. 2009 Jun 16;106(24):9737-42. doi: 10.1073/pnas.0900229106. Epub 2009 Jun 1.
The genetic coupling hypothesis of signal-preference evolution, whereby the same genes control male signal and female preference for that signal, was first inspired by the evolution of cricket acoustic communication nearly 50 years ago. To examine this hypothesis, we compared the genomic location of quantitative trait loci (QTL) underlying male song and female acoustic preference variation in the Hawaiian cricket genus Laupala. We document a QTL underlying female acoustic preference variation between 2 closely related species (Laupala kohalensis and Laupala paranigra). This preference QTL colocalizes with a song QTL identified previously, providing compelling evidence for a genomic linkage of the genes underlying these traits. We show that both song and preference QTL make small to moderate contributions to the behavioral difference between species, suggesting that divergence in mating behavior among Laupala species is due to the fixation of many genes of minor effect. The diversity of acoustic signaling systems in crickets exemplifies the evolution of elaborate male displays by sexual selection through female choice. Our data reveal genetic conditions that would enable functional coordination between song and acoustic preference divergence during speciation, resulting in a behaviorally coupled mode of signal-preference evolution. Interestingly, Laupala exhibits one of the fastest rates of speciation in animals, concomitant with equally rapid evolution in sexual signaling behaviors. Genomic linkage may facilitate rapid speciation by contributing to genetic correlations between sexual signaling behaviors that eventually cause sexual isolation between diverging populations.
信号偏好进化的基因耦合假说认为，相同的基因控制着雄性信号以及雌性对该信号的偏好，这一假说最初是近50年前受蟋蟀声学通讯进化的启发而提出的。为了检验这一假说，我们比较了夏威夷蟋蟀属Laupala中雄性鸣声和雌性声学偏好变异所涉及的数量性状位点（QTL）的基因组位置。我们记录了两个近缘物种（考艾岛Laupala蟋蟀和黑翅Laupala蟋蟀）之间雌性声学偏好变异所涉及的一个QTL。这个偏好QTL与之前鉴定出的一个鸣声QTL共定位，为这些性状背后的基因存在基因组连锁提供了有力证据。我们表明，鸣声和偏好QTL对物种间行为差异的贡献都较小到中等，这表明Laupala物种间交配行为的差异是由于许多微效基因的固定。蟋蟀声学信号系统的多样性体现了通过雌性选择进行性选择导致雄性复杂展示的进化过程。我们的数据揭示了在物种形成过程中，能够使鸣声和声学偏好分化之间实现功能协调的遗传条件，从而导致信号偏好进化的行为耦合模式。有趣的是，Laupala展现出动物中最快的物种形成速度之一，同时伴随着性信号行为同样快速的进化。基因组连锁可能通过促进性信号行为之间的遗传相关性来推动快速物种形成，最终导致分化种群之间的性隔离。
