Molecular basis and evolution of visual mate recognition in Heliconius butterflies

对不同生态位的适应可以导致新物种的进化，进化生物学的一个主要目标是确定种群差异背后的遗传变化。相对于形态特征，在自然界中观察到的行为差异的遗传学还没有很好地表征。对于导致生殖隔离的行为尤其如此。然而，这些行为，如选择性配偶偏好，在种群分化过程中迅速进化，在新物种进化过程中很重要。蝴蝶是仅有的几个系统之一，在它们的生态环境中，有可能完全剖析配偶识别行为的遗传和进化历史。这个新热带属以其明亮的警告模式而闻名，并在适应和物种形成方面得到了特别好的研究。由于选择模仿，近亲物种经常使用相同的警告模式。然而，密切相关的物种可能看起来非常不同，而非模仿的杂交物种不会被认为是令人讨厌的，它们会遭受更多的捕食。颜色模式的变化也会导致行为隔离，因为雄性对自己的翅膀模式比近亲物种更偏爱。然而，虽然现在对预警模式的遗传学有了非常详细的了解，但我们对分子水平上相应行为的理解仍然有限。我的研究旨在确定蝴蝶视觉配偶识别的因果基因。我将首先开发新的方法来有效和准确地量化视觉吸引力。通过将现代分子技术与大型测绘人群的准确行为数据相结合，我将确定视觉吸引力差异背后的狭窄基因组区域。这些分析将在生态上不同的同域物种之间进行，然后在不接触的物种之间进行。这将测试物种形成研究的一个关键假设，即控制导致保持接触的种群之间生殖隔离的行为和生态特征的位点聚集在基因组中。在多个物种对中确定候选区域也将有助于基因组分析，从而进一步了解视觉吸引力的遗传基础。我将把这些分析与表达研究结合起来，最终目的是为功能实验提供候选者。这项工作将为物种形成提供新的见解，这是进化和生物多样性的基础过程，但也对我们理解生态相关行为的遗传学有更广泛的影响。

Adaptation to different ecological niches can result in the evolution of new species, and a major goal of evolutionary biology is to identify the genetic changes underlying population divergence. Relative to morphological traits, the genetics of behavioural differences observed in nature have not been well characterized. This is especially true for behaviours that contribute to reproductive isolation. However, these behaviours, such as assortative mate preferences, are known to evolve rapidly during population divergence and are important during the evolution of new species. The Heliconius butterflies are one of only a few systems in which it will be possible to fully dissect the genetics and evolutionary history of mate recognition behaviours within their ecological context. This Neotropical genus is well known for its bright warning patterns, and has been especially well studied with respect to adaptation and speciation. Distantly related species often use the same warning pattern due to selection for mimicry. However, closely related species can look very different and non-mimetic hybrids, which are not recognized as distasteful, suffer increased predation. Shifts in colour pattern also result in behavioural isolation as males show a preference for their own wing pattern over that of closely related species. However, while the genetics of warning pattern are now known in fantastic detail, our understanding of the corresponding behaviours at the molecular level remains limited. My research aims to identify the causal genes underlying visual mate recognition in Heliconius butterflies. I will first develop novel methods to efficiently and accurately quantify visual attraction. By combining modern molecular techniques with accurate behavioural data for a large mapping population, I will identify narrow genomic regions underlying differences in visual attraction. These analyses will be conducted between ecologically divergent species that are sympatric, and then between species which are not in contact. This will test a key hypothesis of speciation research that loci controlling behavioural and ecological traits that cause reproductive isolation between populations that remain in contact are clustered in the genome. Identifying the candidate regions in multiple species pairs will also facilitate genomic analyses to further key in on the genetic basis of visual attraction. I will combine these analyses with expression studies with the ultimate goal of providing candidates for functional experiments. This work will offer new insights into speciation, a process fundamental to evolution and biodiversity, but also has wider implications for our understanding of the genetics of ecologically relevant behaviours.