鸮形目鸟类视听感官基因的补偿进化研究

Are there any compensatory evolution of one sensory system as the functional performances of other sensory systems are constrained? Here we would use owls as a model system to examine the possible compensatory evolution relationships between sensory systems. Adapted to dim-light environments, owls have evolved great scotopic vision and sensitive hearing, which may be a result of their less usage of the photopic vision. If the compensatory evolution occurs between the visual system and the auditory system in owls, we would predict that some scotopic vision genes and hearing genes of owls may have undergone adaptive accelerated evolution, whereas some photopic vision genes may be subjected to reduced expression level or becoming pseudogenes compared with that of their diurnal relatives. To test these predictions, based on the global owl species sampling, we will perform comparative analyses of molecular sensory ecology of owls and their diurnal relatives based on both the gene expression analyses and the gene function analyses. This would help to explore the molecular basis of the specialization of the vision system and the auditory system of owls, and more importantly help to test possible existence of the compensatory evolution relationships between the two sensory systems. The possible findings of this study will help to understand if the interactions of the vision system and the auditory system will affect their evolution, advancing our understanding of the evolutionary mechanisms of biological traits.

一种感官功能发挥受限是否会导致其它感官功能发生适应性进化增强？本研究拟以夜行性鸮形目鸟类为研究对象对该问题进行研究。鸮类适应夜行生活，其发达的暗视觉与敏锐听觉可能是对其夜行活动中明视觉功能相对退化的一种补偿性进化结果。如果这种补偿关系存在，则可预测，与昼行性近缘类群相比，鸮类暗视觉基因与听觉基因可能发生了加速适应性进化，而其明视觉基因则可能由于选择压力松弛而导致功能部分丧失。为检验该预测，在本项目组前期研究基础之上，本研究将进一步扩大样品种类覆盖范围，在全球鸮形目鸟类样品采集的基础上，从组学水平上拟对鸮形目及其昼行性近缘类群的视觉与听觉分子感官生态进一步深入研究，同时从基因表达以及基因功能两个水平揭示鸮类视觉与听觉特化的分子机制及其可能存在的补偿进化关系。对感官补偿进化现象进行研究不但有助于从感官系统互作角度认识动物感官进化的内在动力，而且对深入理解生物性状的进化机制具重要意义。

动物视觉基因进化与其昼夜活动模式的关系尚不清楚。本项研究通过比较不同昼夜活动模式（昼行与夜行）类群视觉基因的进化，结果显示昼行类群的明视觉基因显示出进化强化，而夜行类群的暗视觉基因则显示出进化强化。这说明动物的昼夜活动模式和视觉基因的进化具有正相关关系。基于此发现，本研究发展了可以通过视觉基因进化来推断动物类群祖先昼夜活动模式的分子方法。通过该分子方法在不同动物类群的应用，重建了相关动物类群祖先的昼夜活动模式，为理解不同动物类群进化起源的选择压力提供了分子数据。在视觉基因研究结果的基础上，本项研究又进一步拓展研究了消化系统基因的进化，揭示了消化系统基因进化与食性的相关关系，结果显示消化系统基因可以反映不同动物类群食性的变化。基于此结果，本项研究又发展了重建动物祖先类群食性的分子方法。总而言之，通过本项研究，项目组发展了重建动物类群祖先性状的分子方法。该分子方法为理解相关动物类群的进化起源提供了新思路。