鲸类次生性水生适应中体型改变的进化遗传学机制

鲸类祖先从陆地重返海洋是生物进化史上最神奇的事件之一。在从陆地重返海洋并最终完全适应水生生活的过程中，鲸类祖先经历了一系列形态、解剖和生理等方面的适应，而体型变为流线型是其中最显而易见的表型改变，但迄今为止对其进化机制所知甚少。鲸类的流线型体型是涉及到骨骼、皮肤、皮下脂肪等多方面的复杂性表型，因此对其进化机制的揭示需要对相关基因、基因家族及代谢通路进行全面系统的分析。本项目拟整合鲸类代表性类群的基因组序列信息，并与近缘陆生动物及其它水生哺乳动物的基因组数据合并，进行系统的比较基因组学和生物信息学分析，以筛选鲸类基因组中受正选择作用的体型相关重要功能基因，揭示这些基因在鲸类中的进化格局及与其它水生哺乳动物之间的趋同适应，结合对重要候选基因在更多物种中的克隆验证和必要的功能实验分析，较为系统地揭示鲸类体型改变的进化遗传学基础及其在次生性水生适应中的作用。

The returning from land to sea of catceans is one of the most mysterious events in evolution. During their secondary transition from land to sea, cetaceans experienced a series of adaptations in morphology, anatamy, and physiology etc, with the change of body plan from the terrestrial limbs type in land mammals to the streamline type in marine mamals. However, up to now, only a little is known about the evolutionary mechenism of such a body plan change. The streamline body in cetaceans is a complex phenotype which is related with many changes in skeleton, skin, and subcutaneous fat (blubber), etc, thus the uncovering its evolutionary mechanism needs a comprehensive and systematic survey of related genes, gene families, and metabolic pathways. In the present study, we plan to integrate genomic data of cetaceans, in combination with genomic data of relevant land mammas and other marine mammals, and with systematic analyses of comparative genomics and bioinformatics, to identify some positively selected genes related with body plan. Through the investigation of evolutonary pattern of these genes in cetaceans and their convergence with other marine mammals, the molecular confirmation of these genes in more represent cetaceans using gene cloning, and necessary function experiments of genes of strong interest, we aim to reveal the evolutionary genetic basis underlying the dramatic body plan change and its significance in the secondary aquatic adaptation of cetaceans.