A postgenomic approach to the role of odour and gustatory receptors in speciation

所有动物都依赖于感知环境中的挥发性和非挥发性化学物质(分别是气味和味觉)。它们利用这些信息来探测食物、躲避捕食者、寻找配偶和其他重要功能。化学感官与其他感官不同，因为它们需要对每一种化合物或每一类化合物做出反应的特定受体。最近，在很大程度上通过基因组测序计划，编码气味和味觉受体的基因类别已经被识别出来，它们的特征现在正在迅速进行。它们很可能是在许多情况下理解化学信息识别和处理的关键。气味和味觉信号通过它们在栖息地和配偶选择中的作用，在许多动物的物种形成中发挥核心作用，这可以说是繁殖隔离的两种主要形式。因此，气味和味觉受体基因类别的鉴定提供了一个令人兴奋的机会，可以系统地研究物种形成过程中这一关键组成部分的遗传基础。在这个项目中，我们将利用黑腹果蝇亚群的基因组信息和物种来调查选定的气味和味觉受体基因座，以寻找物种内和物种间的差异。我们将比较物种间的序列差异和物种内的变异水平，以检测在自然选择下快速进化的基因座。我们将在物种间杂交的重组近交系中测试气味和味觉受体基因座与关键行为特征(如配偶和栖息地选择)之间的关联。这将证实候选基因座在关键行为步骤中的作用。我们将检查同一组菌株的基因表达，以测试具有改变表达模式和潜在新功能的基因座。这将为结构和表达修饰在适应性进化中的相对作用这一长期存在的问题提供一个系统的答案，并指出候选的“物种形成基因”。该项目是三个在这一领域具有互补专业知识的实验室之间的合作。除了对物种形成遗传学的无与伦比的洞察外，该项目还将提供关于这些迷人而重要的基因进化的新数据，并对它们在许多其他物种和背景下的研究产生影响，包括病虫害和病媒控制。

All animals rely on sensing volatile and non-volatile chemicals in their environment (odour and gustatory senses, respectively). They use this information for detecting food, avoiding predators, finding mates and other crucial functions. The chemical senses are unlike other senses in that they require specific receptors for each compound or class of compounds to which they respond. Recently, in large part through genome sequencing projects, classes of genes coding for odorant and gustatory receptors have been identified and their characterisation is now proceeding rapidly. They may well be the key to understanding the recognition and processing of chemical information in many contexts. Odour and gustatory signals have central roles in speciation in many animals through their functions in both habitat and mate choice, arguably the two primary forms of premating reproductive isolation. The identification of odorant and gustatory receptor gene classes thus provides an exciting opportunity to take a systematic approach to the genetic basis of this key component of the speciation process. In this project, we will use genomic information and species of the Drosophila melanogaster subgroup to survey selected odorant and gustatory receptor loci for variation within and between species. We will compare sequence divergence between species with levels of variation within species to detect loci that have evolved rapidly under natural selection. We will test for associations between odorant and gustatory receptor loci and key behavioural traits, such as mate and habitat choice, in recombinant inbred lines of crosses between species. This will confirm the roles of candidate loci in critical behavioural steps. We will examine gene expression in the same set of strains to test for loci that have altered expression patterns and so potentially novel functions. This will provide a systematic answer to the longstanding question of the relative roles of structural and expression modifications in adaptive evolution as well as pointing to candidate 'speciation genes'. The project is a collaboration between three laboratories with complementary expertise in this area. As well as the unparalleled insight into the genetics of speciation, the project will provide new data on the evolution of these fascinating and important genes with implications for their study in many other species and contexts including pest and disease vector control.