Molecular Evolution of Vertebrate Visual Systems

确定生物体如何适应环境是进化生物学的一个基本目标。感官系统，如视觉，是研究这一主题的理想模型，因为它们提供了生物体与其环境之间的直接接口。我的研究计划的长期目标是更好地了解脊椎动物视觉系统的进化，以及它们如何发展和适应不同的感官环境。我的研究采用了一种创新和综合的方法，将比较基因组学和进化计算分析与有针对性的实验相结合，以提供视觉系统在多个组织尺度上的进化和功能的全面视图。两栖动物（青蛙、蝾螈和无尾螈）为研究视觉系统的进化和适应提供了一个很好的系统。它们是一个多样化的群体（约8200种），进化出许多不同的生活史和行为，包括地下生活方式，为研究视觉系统的重复适应提供了机会。两栖动物也概括了脊椎动物从水生环境到陆地环境的重要进化转变，这对视觉系统施加了截然不同的光谱和光学限制。这种从水生环境到陆地环境的转变也发生在许多两栖动物的生命周期中，从水生幼虫（蝌蚪）到陆地幼体，进一步为探索视觉系统适应的进化和发展的交叉点提供了机会。两栖动物还具有一种新型的光敏感光器，当大多数其他动物都是色盲时，这种感光器可以在昏暗的光线下实现夜间的彩色视觉。尽管两栖动物的这些独特方面使它们成为视觉生物学的一个特别引人注目的模型，但两栖动物视觉系统的研究远远落后于其他脊椎动物群体。我们将对两栖动物的视觉基因进化进行首次综合分析，深入了解视觉系统对进化新的生活史模式和行为的解决方案的限制和机会。对青蛙和蝾螈视觉基因在个体发育过程中的表达进行补充研究，将揭示发育变化在视觉适应中的作用。我们还将使用比较基因组方法研究两栖动物和爬行动物的视觉适应，这些两栖动物和爬行动物趋同地进化出地下生活方式。最后，我们将利用单细胞转录组测序和细胞成像来研究这种新型两栖动物光感受器，以揭示其进化和发育历史。这将为进一步研究脊椎动物光感受器的进化和发育奠定基础。该研究项目将为多样化的学员群体创造一个丰富的环境，使他们能够利用进化基因组学的尖端技术做出重大贡献。

Determining how organisms adapt to their environments is a fundamental goal of evolutionary biology. Sensory systems, such as vision, are an ideal model to study this topic, as they provide a direct interface between an organism and its environment. The long-term objective of my research program is to better understand the evolution of vertebrate visual systems and how they develop and adapt in response to different sensory environments. My research takes an innovative and integrative approach that combines comparative genomics and evolutionary computational analyses with targeted experiments to provide a comprehensive view of visual system evolution and function at multiple organizational scales. Amphibians (frogs, salamanders, and caecilians) provide an excellent system within which to study the evolution and adaptation of visual systems. They are a diverse group (~8200 species) that has convergently evolved many different life histories and behaviors, including subterranean lifestyles, providing the opportunity to study repeated adaptation in the visual system. Amphibians also encapsulate an important evolutionary transition in vertebrate evolution from aquatic to terrestrial environments, which imposed drastically different spectral and optical constraints on the visual system. This transition between aquatic and terrestrial environments also occurs during the life cycle of many amphibians with the transition from aquatic larvae (tadpoles) to terrestrial juveniles, further providing an opportunity to explore the intersection of evolution and development in adaptation of the visual system. Amphibians also have a novel type of light-sensitive photoreceptor that may enable nocturnal colour vision in dim light when most other animals are colour-blind. Despite these unique aspects of amphibians that make them a particularly compelling model for visual biology, the study of amphibian visual systems has fallen well behind other vertebrate groups. We will conduct the first integrative analysis of visual gene evolution across amphibians providing deep insight into the constraints and opportunities of visual systems to evolving novel solutions to new life history modes and behaviors. Complementary studies of frog and salamander visual gene expression across ontogeny will reveal the role of developmental changes in visual adaptation. We will also investigate visual adaptation in amphibians and reptiles that convergently evolved subterranean lifestyles using comparative genomic approaches. Finally, we will study the novel amphibian photoreceptor using single cell transcriptome sequencing and cellular imaging to uncover its evolutionary and developmental history. This will further lay the foundation for future studies of photoreceptor evolution and development in vertebrates. This research program will create a rich environment for a diverse group of trainees to make major contributions using cutting-edge techniques in evolutionary genomics.