Rapid evolution of chemosensory receptor genes in a pair of sibling species of orchid bees (Apidae: Euglossini).
Rapid evolution of chemosensory receptor genes in a pair of sibling species of orchid bees (Apidae: Euglossini).
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DOI：
10.1186/s12862-015-0451-9
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发表时间：
2015-08-28
影响因子：
3.4
通讯作者：
Eltz T
中科院分区：
文献类型：
--
作者：
Brand P;Ramírez SR;Leese F;Quezada-Euan JJ;Tollrian R;Eltz T
昆虫更依赖于化学信号（化学信息素），而不是任何其他感官形式来寻找，识别和选择配偶。在大多数昆虫中，信息素的产生通常通过生物合成途径来调节，而信息素的感觉检测则由嗅觉系统控制。兰花蜜蜂的特殊之处在于它们的化学信息素不是通过代谢产生的，而是雄性蜜蜂从环境中收集有气味的化合物（香水），并将其储存在专门的后腿口袋中，随后在求偶时暴露。因此，兰花蜜蜂的嗅觉系统同时控制男性香水性状（发送器组件）和女性的喜好（接收器组件）。这种功能联系增加了男性特征和女性偏好平行进化的机会，特别是在响应化学传感检测的遗传变化（例如气味受体基因）时。为了确定是否在信息素组成的变化相关血统的兰花蜜蜂与分歧化学感受基因的嗅觉外围，我们寻找了两个最近分歧的兄弟物种Euglossa困境和E的触角转录组的分歧选择模式。精力充沛我们鉴定了3185个直向调节基因，包括来自5个不同基因家族（气味受体、离子亲性受体、味觉受体、气味结合蛋白和化学感受蛋白）的94个化学感受位点。我们的研究结果表明，具有E. dilemma和E. viridissima显著富集了化学感受基因。值得注意的是，几乎仅在化学感受受体（即气味受体）中观察到趋异选择的升高信号。我们的研究结果表明，快速变化的化学感受基因家族之间发生密切相关的兰花蜜蜂物种。这些发现与强烈趋异选择作用于化学感受受体基因在昆虫信息素系统的进化和多样化中起重要作用的假设是一致的。本文的在线版本（doi：10.1186/s12862-015-0451-9）包含补充材料，可供授权用户使用。
Insects rely more on chemical signals (semiochemicals) than on any other sensory modality to find, identify, and choose mates. In most insects, pheromone production is typically regulated through biosynthetic pathways, whereas pheromone sensory detection is controlled by the olfactory system. Orchid bees are exceptional in that their semiochemicals are not produced metabolically, but instead male bees collect odoriferous compounds (perfumes) from the environment and store them in specialized hind-leg pockets to subsequently expose during courtship display. Thus, the olfactory sensory system of orchid bees simultaneously controls male perfume traits (sender components) and female preferences (receiver components). This functional linkage increases the opportunities for parallel evolution of male traits and female preferences, particularly in response to genetic changes of chemosensory detection (e.g. Odorant Receptor genes). To identify whether shifts in pheromone composition among related lineages of orchid bees are associated with divergence in chemosensory genes of the olfactory periphery, we searched for patterns of divergent selection across the antennal transcriptomes of two recently diverged sibling species Euglossa dilemma and E. viridissima. We identified 3185 orthologous genes including 94 chemosensory loci from five different gene families (Odorant Receptors, Ionotropic Receptors, Gustatory Receptors, Odorant Binding Proteins, and Chemosensory Proteins). Our results revealed that orthologs with signatures of divergent selection between E. dilemma and E. viridissima were significantly enriched for chemosensory genes. Notably, elevated signals of divergent selection were almost exclusively observed among chemosensory receptors (i.e. Odorant Receptors). Our results suggest that rapid changes in the chemosensory gene family occurred among closely related species of orchid bees. These findings are consistent with the hypothesis that strong divergent selection acting on chemosensory receptor genes plays an important role in the evolution and diversification of insect pheromone systems. The online version of this article (doi:10.1186/s12862-015-0451-9) contains supplementary material, which is available to authorized users.