Department of Bioinformatics, Program in Sciences Mention Modeling of Chemical and Biological Systems, School of Bioinformatics Engineering, Center for Bioinformatics, Simulation and Modeling, CBSM, Faculty of Engineering, University of Talca, Campus Talca, Talca, Chile.
Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas-UNICAMP, Cidade Universitária, Campinas, Brazil.
Sci Rep. 2024 Jul 23;14(1):17024. doi: 10.1038/s41598-024-66082-1.
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.
鲸目动物代表了生命之树上的一个自然实验，其中一个谱系从陆地栖息地转变为水生栖息地。这种转变涉及表型修饰，为探索表型多样性的遗传基础提供了机会。在维持细胞内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都是至关重要的。本研究旨在探索鲸目动物进化过程中离子通道的进化。为此，我们创建了一个生物信息学管道，以注释我们采样物种基因组中的离子通道库。我们的主要结果表明，鲸目动物的平均蛋白编码基因较少，注释的离子通道百分比高于非鲸目哺乳动物。在与心脏、运动、视觉和神经表型相关的离子通道中检测到了正选择信号。有趣的是，我们预测大多数齿鲸（齿鲸目）的 NaV1.5 离子通道对河豚毒素敏感，类似于 NaV1.7，因为在离子通道的特定位置存在酪氨酸而不是半胱氨酸。最后，鲸目动物冠群的基因周转率比非鲸目哺乳动物快三倍多。
