Centre National de la Recherche Scientifique, UMR 7261, IRBI, Université François Rabelais de Tours, Parc de Grandmont, Tours, France.
PLoS One. 2012;7(9):e44554. doi: 10.1371/journal.pone.0044554. Epub 2012 Sep 5.
Models of indirect (genetic) benefits sexual selection predict linkage disequilibria between genes that influence male traits and female preferences, owing to non-random mate choice or physical linkage. Such linkage disequilibria can accelerate the evolution of traits and preferences to exaggerated levels. Both theory and recent empirical findings on species recognition suggest that such linkage disequilibria may result from physical linkage or pleiotropy, but very little work has addressed this possibility within the context of sexual selection. We studied the genetic architecture of sexually selected traits by analyzing signals and preferences in an acoustic moth, Achroia grisella, in which males attract females with a train of ultrasound pulses and females prefer loud songs and a fast pulse rhythm. Both male signal characters and female preferences are repeatable and heritable traits. Moreover, female choice is based largely on male song, while males do not appear to provide direct benefits at mating. Thus, some genetic correlation between song and preference traits is expected. We employed a standard crossing design between inbred lines and used AFLP markers to build a linkage map for this species and locate quantitative trait loci (QTL) that influence male song and female preference. Our analyses mostly revealed QTLs of moderate strength that influence various male signal and female receiver traits, but one QTL was found that exerts a major influence on the pulse-pair rate of male song, a critical trait in female attraction. However, we found no evidence of specific co-localization of QTLs influencing male signal and female receiver traits on the same linkage groups. This finding suggests that the sexual selection process would proceed at a modest rate in A. grisella and that evolution toward exaggerated character states may be tempered. We suggest that this equilibrium state may be more the norm than the exception among animal species.
间接（遗传）利益的选择模型预测影响雄性特征和雌性偏好的基因之间的连锁不平衡，这是由于非随机的配偶选择或物理连锁。这种连锁不平衡可以加速特征和偏好的进化到夸张的水平。物种识别的理论和最近的经验发现都表明，这种连锁不平衡可能是由于物理连锁或多效性造成的，但在性选择的背景下，很少有工作涉及到这种可能性。我们通过分析声学飞蛾 Achroia grisella 的性选择特征的信号和偏好，研究了性选择特征的遗传结构，在这种飞蛾中，雄性用一连串超声波脉冲吸引雌性，而雌性则喜欢响亮的歌声和快速的脉冲节奏。雄性信号特征和雌性偏好都是可重复和可遗传的特征。此外，雌性选择主要基于雄性的歌声，而雄性在交配时似乎没有提供直接的利益。因此，预计在歌声和偏好特征之间存在一定的遗传相关性。我们采用了自交系之间的标准杂交设计，并使用 AFLP 标记为该物种构建了一个连锁图谱，并定位了影响雄性歌声和雌性偏好的数量性状基因座（QTL）。我们的分析主要揭示了影响各种雄性信号和雌性接收特征的中等强度的 QTL，但发现了一个 QTL 对雄性歌声的脉冲对率有很大影响，这是雌性吸引力的一个关键特征。然而，我们没有发现影响雄性信号和雌性接收特征的 QTL 在同一连锁群上特定的共定位的证据。这一发现表明，在 A. grisella 中，性选择过程的进展速度适中，并且向夸张的特征状态的进化可能会受到限制。我们认为，这种平衡状态在动物物种中可能更为常见，而不是例外。
