PDF(Pubmed)
Abstract：
Cetaceans represent a natural experiment within the tree of life in which a lineage changed from terrestrial to aquatic habitats. This shift involved phenotypic modifications, representing an opportunity to explore the genetic bases of phenotypic diversity. Among the different molecular systems that maintain cellular homeostasis, ion channels are crucial for the proper physiological functioning of all living species. This study aims to explore the evolution of ion channels during the evolutionary history of cetaceans. To do so, we created a bioinformatic pipeline to annotate the repertoire of ion channels in the genome of the species included in our sampling. Our main results show that cetaceans have, on average, fewer protein-coding genes and a higher percentage of annotated ion channels than non-cetacean mammals. Signals of positive selection were detected in ion channels related to the heart, locomotion, visual and neurological phenotypes. Interestingly, we predict that the NaV1.5 ion channel of most toothed whales (odontocetes) is sensitive to tetrodotoxin, similar to NaV1.7, given the presence of tyrosine instead of cysteine, in a specific position of the ion channel. Finally, the gene turnover rate of the cetacean crown group is more than three times faster than that of non-cetacean mammals.
摘要：
鲸目动物代表了生命树中的自然实验，其中血统从陆地栖息地变为水生栖息地。这种转变涉及表型修饰，代表了探索表型多样性遗传基础的机会。在维持细胞稳态的不同分子系统中，离子通道对于所有生物物种的正常生理功能至关重要。本研究旨在探讨鲸目动物进化史中离子通道的演化规律。要做到这一点，我们创建了一个生物信息学管道来注释我们采样中包含的物种基因组中的离子通道库。我们的主要研究结果表明鲸目动物,平均而言,与非鲸目哺乳动物相比，蛋白质编码基因更少，注释离子通道的百分比更高。在与心脏相关的离子通道中检测到阳性选择信号，运动，视觉和神经表型。有趣的是,我们预测大多数齿鲸的NaV1.5离子通道对河豚毒素敏感，类似于NaV1.7，由于存在酪氨酸而不是半胱氨酸，在离子通道的特定位置。最后,鲸类冠类的基因转换率比非鲸类哺乳动物快三倍以上。
