The genetic basis of convergence across evolutionary time

跨进化时间趋同的遗传基础

• 批准号: NE/T008121/1
• 负责人: Kanchon Dasmahapatra
• 金额: $ 81.95万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT008121%2F1
• 关键词: genetic; basis; convergence; across; evolutionary

Convergent evolution, the independent acquisition of similar traits in multiple lineages in response to the same selective pressures, is ubiquitous, facilitating adaptation and diversification across the tree of life. Therefore, understanding the genetic mechanisms by which convergence occurs is critical if we are to understand adaptations that already exist, and the predictability of evolution in response to common selection pressures. We propose to study mimetic convergence across the Lepidoptera using high-throughput sequencing and gene expression analyses to address a major challenge in this field: the contributions of different genetic mechanisms to convergence across evolutionary timescales. This will be the first genetic analysis of convergence for a trait evolving under the same selective force over 2-110 million years of evolution and will uncover the genetic landscape of convergence across evolutionary time.The genetic changes causing convergence can be categorized as divergent genetic mechanisms, parallel evolution, or collateral evolution. We hypothesize that these three processes act at different evolutionary time scales. Most recent understanding of convergent evolution has focused on parallel and collateral evolution among closely related species. We lack studies that investigate the genetic basis of convergence over a range divergence times (from recent to deep time) for a single trait under the same selective force. Only by considering convergence among lineages that split anywhere from a few million to 100 million years ago, or more, can we understand the overall frequency distribution of the genetic mechanisms of convergence. The relative contributions of the three genetic mechanisms will impact on the tempo and direction of evolutionary convergence. For example, interspecific hybridization can greatly facilitate convergence among closely-related species, yet its contribution to convergence is largely unknown. We also lack knowledge of the genetic basis of deep time convergence. An important unanswered question is whether convergence between distant lineages is difficult to evolve. Alternatively, is convergence aided by the existence of conserved genetic architectures and developmental pathways, which may facilitate parallel evolution even after 100 million years of separation? We propose to tackle these fundamental questions about the genetic mechanisms of convergence by exploiting a unique system in the Lepidoptera in which multiple species have converged on the same defensive wing colour patterns across a wide range of evolutionary timescales (2-110 million years). We will use a combination of fieldwork, gene expression analysis and the latest high-throughput sequencing technologies to identify and verify genes responsible for convergence in multiple butterfly and moth species. These data will allow us to assess the relative contributions of divergent genetic mechanisms, parallel and collateral evolution to convergence among 18 species of butterflies and moths representing 2-110 million years of evolution, and will allow us for the first time to visualize the genetic landscape of convergent evolution for a single trait evolving under the same selective force across a wide evolutionary timescale.

趋同进化，即在相同的选择压力下，在多个谱系中独立获得相似的性状，是普遍存在的，促进了整个生命之树的适应和多样化。因此，如果我们要理解已经存在的适应性，以及对共同选择压力的可预测性，那么了解趋同发生的遗传机制至关重要。我们建议使用高通量测序和基因表达分析来研究整个鳞翅目昆虫的拟态收敛，以解决这一领域的一个主要挑战：不同遗传机制对进化时间尺度上收敛的贡献。这将是第一次对在200万至1.1亿年的进化过程中在同一选择力下进化的性状进行趋同的遗传分析，并将揭示进化过程中趋同的遗传景观。导致趋同的遗传变化可分为分歧遗传机制、平行进化或侧系进化。我们假设这三个过程在不同的进化时间尺度上起作用。最近对趋同进化的理解集中在密切相关的物种之间的平行和并行进化。我们缺乏研究，调查收敛的遗传基础上的一个范围内的分歧时间（从最近到深的时间）为一个单一的性状在相同的选择力。只有考虑到在几百万年到一亿年前或更久以前分裂的血统之间的趋同性，我们才能理解趋同性遗传机制的总体频率分布。这三种遗传机制的相对贡献将影响进化趋同的克里思和方向。例如，种间杂交可以极大地促进近缘物种之间的趋同，但其对趋同的贡献在很大程度上是未知的。我们也缺乏对深时间收敛的遗传基础的了解。一个尚未回答的重要问题是，遥远血统之间的趋同是否难以进化。或者，趋同是由保守的遗传结构和发育途径的存在所帮助的，即使在1亿年的分离之后，这些遗传结构和发育途径也可能促进平行进化？我们建议解决这些基本问题的遗传机制的收敛，利用一个独特的系统，在鳞翅目中，多个物种在广泛的进化时间尺度（2- 1.1亿年）相同的防御翅膀颜色模式的收敛。我们将使用实地考察，基因表达分析和最新的高通量测序技术相结合，以确定和验证基因负责收敛在多个蝴蝶和蛾物种。这些数据将使我们能够评估代表2- 1.1亿年进化的18种蝴蝶和飞蛾之间的分歧遗传机制，平行和并行进化对趋同的相对贡献，并将使我们首次可视化在广泛的进化时间尺度上在相同选择力下进化的单一性状的趋同进化的遗传景观。