Shaw Kerry L, Parsons Yvonne M, Lesnick Sky C
Department of Biology, University of Maryland, College Park, MD 20742, USA.
Mol Ecol. 2007 Jul;16(14):2879-92. doi: 10.1111/j.1365-294X.2007.03321.x.
In mate recognition systems, the functional necessity to coordinate traits involved in sexual communication should result in reduced pairing potential for new variants outside the distribution of common reproductive signals. Yet, many closely related, sexual species differ in mate recognition traits, suggesting that directional selection influences the divergence of mate recognition systems. Species of the endemic Hawaiian cricket genus Laupala are morphologically and ecologically cryptic, although both male calling song and female acoustic preference have diverged rapidly between closely related species. These mate recognition phenotypes are therefore often likely to be speciation phenotypes, i.e. traits whose divergence contributes, directly or indirectly, to a reduction of gene flow during speciation, given their frequent participation in early lineage divergence. We conducted a replicated, quantitative trait loci (QTL) mapping study of the genetic basis of differences in male calling song between two closely related species, Laupala paranigra and Laupala kohalensis, allowing us to examine the genetic basis of traits involved in rapid speciation. We found statistical support for eight QTL in one replicate, with at least four of these QTL mapping to the same regions in a second replicate. QTL effects ranged between 3.0% and 10.7% of the difference in pulse rate between L. paranigra and L. kohalensis, and are thus of moderate to small effect. All QTL identified show directional effects consistent with the hypothesis of directional selection. Thus, we conclude that rapid speciation can occur under the influence of many genes of moderate to small effect. This study implicates the role of directional selection in the divergence of mate recognition traits and speciation the Hawaiian cricket genus Laupala.
在配偶识别系统中，协调参与性交流的性状的功能必要性应导致常见生殖信号分布范围之外的新变异体的配对潜力降低。然而，许多亲缘关系密切的有性物种在配偶识别性状上存在差异，这表明定向选择影响着配偶识别系统的分化。夏威夷特有蟋蟀属Laupala的物种在形态和生态上难以区分，尽管雄性求偶鸣叫和雌性声学偏好在亲缘关系密切的物种之间迅速分化。因此，这些配偶识别表型往往可能是物种形成表型，即其分化直接或间接地有助于在物种形成过程中减少基因流动的性状，因为它们经常参与早期谱系分化。我们对两个亲缘关系密切的物种Laupala paranigra和Laupala kohalensis之间雄性求偶鸣叫差异的遗传基础进行了重复的数量性状基因座（QTL）定位研究，从而使我们能够研究参与快速物种形成的性状的遗传基础。我们在一次重复实验中发现了对8个QTL的统计支持，其中至少有4个QTL在第二次重复实验中定位到相同区域。QTL效应在Laupala paranigra和Laupala kohalensis脉冲率差异的3.0%至10.7%之间，因此效应为中等至较小。所有鉴定出的QTL都显示出与定向选择假说一致的定向效应。因此，我们得出结论，快速物种形成可以在许多效应中等至较小的基因的影响下发生。这项研究暗示了定向选择在配偶识别性状分化和夏威夷蟋蟀属Laupala物种形成中的作用。
