Understanding the importance of convergent vs. lineage-specific molecular changes for convergent adaptations

在独立谱系中相似特征的趋同进化是最令人着迷的进化现象之一。先前的研究揭示了一些显著的例子，其中相似或有时相同的基因组变化是表型趋同的基础，这提出了一个基本问题：趋同与谱系特异性分子变化对表型趋同的贡献是什么？本项目将利用独立的果食性和食性蝙蝠谱系中对富含糖的饮食的趋同适应作为一种可处理的模型来解决这个问题。我们将采用一种整合的方法，包括：(i)生成高度连续和完整的战略选择蝙蝠基因组，以及与糖和胰岛素代谢相关的关键组织的基因表达数据，（ii）应用基因组学方法筛选编码基因中的五种类型的突变特征，从而全面确定与趋同糖饮食适应相关的趋同和谱系特异性基因变化。（iii）系统地识别食果和食糖蝙蝠基因表达的趋同和谱系特异性转移。总之，这将首次全面揭示这些蝙蝠对适应富含糖的饮食的重要的收敛性和谱系特异性变化，这也可能发现与人类代谢紊乱相关的有希望的靶标。总的来说，该项目将为长期存在的关于趋同与谱系特异性以及基因序列与基因表达变化对表型趋同的重要性的问题提供新的见解。

Convergent evolution of similar traits in independent lineages represents one of the most fascinating evolutionary phenomena. Previous studies revealed remarkable examples where similar or sometimes the same genomic changes underlie phenotypic convergence, which raises a fundamental question: What is the contribution of convergent vs. lineage-specific molecular changes to phenotypic convergence?This project will address this question using convergent adaptations to a sugar-rich diet in independent lineages of frugivorous and nectarivorous bats as a tractable model. We will use an integrative approach that comprises (i) generating highly-contiguous and complete genomes of strategically-selected bats together with gene expression data of key tissues relevant for sugar and insulin metabolism, (ii) applying genomic methods to screen genome-wide for five types of mutational signatures in coding genes and thus comprehensively determine convergent and lineage-specific gene changes that are relevant for convergent sugar diet adaptations, and (iii) systematically identifying convergent and lineage-specific shifts in gene expression in frugi- and nectarivorous bats. Together, this will reveal the first comprehensive picture of convergent as well as lineage-specific changes that are important for adaptations to sugar-rich diets in these bats, which may also uncover promising targets with relevance for human metabolic disorders. Overall, this project will provide novel insights into long-standing questions concerning the importance of convergent vs. lineage-specific and gene-sequence vs. gene-expression changes for phenotypic convergence.