Lorente-Martínez Héctor, Agorreta Ainhoa, Irisarri Iker, Zardoya Rafael, Edwards Scott V, San Mauro Diego
Department of Biodiversity, Ecology, and Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain.
Section Phylogenomics, Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum of Nature Hamburg, 20146 Hamburg, Germany.
Biology (Basel). 2023 Jun 12;12(6):846. doi: 10.3390/biology12060846.
Aquaporins (AQPs) are a highly diverse family of transmembrane proteins involved in osmotic regulation that played an important role in the conquest of land by tetrapods. However, little is known about their possible implication in the acquisition of an amphibious lifestyle in actinopterygian fishes. Herein, we investigated the molecular evolution of AQPs in 22 amphibious actinopterygian fishes by assembling a comprehensive dataset that was used to (1) catalogue AQP paralog members and classes; (2) determine the gene family birth and death process; (3) test for positive selection in a phylogenetic framework; and (4) reconstruct structural protein models. We found evidence of adaptive evolution in 21 AQPs belonging to 5 different classes. Almost half of the tree branches and protein sites that were under positive selection were found in the AQP11 class. The detected sequence changes indicate modifications in molecular function and/or structure, which could be related to adaptation to an amphibious lifestyle. AQP11 orthologues appear to be the most promising candidates to have facilitated the processes of the water-to-land transition in amphibious fishes. Additionally, the signature of positive selection found in the AQP11b stem branch of the Gobiidae clade suggests a possible case of exaptation in this clade.
水通道蛋白（AQPs）是一类高度多样的跨膜蛋白，参与渗透调节，在四足动物征服陆地的过程中发挥了重要作用。然而，关于它们在辐鳍鱼类获得两栖生活方式中可能的作用却知之甚少。在此，我们通过组装一个综合数据集，研究了22种两栖辐鳍鱼类中AQPs的分子进化，该数据集用于：（1）编目AQP旁系同源成员和类别；（2）确定基因家族的生死过程；（3）在系统发育框架下检测正选择；（4）重建结构蛋白模型。我们发现了属于5个不同类别的21种AQPs存在适应性进化的证据。在AQP11类别中发现了几乎一半处于正选择状态的树分支和蛋白位点。检测到的序列变化表明分子功能和/或结构发生了改变，这可能与适应两栖生活方式有关。AQP11直系同源物似乎是促进两栖鱼类从水生到陆生转变过程的最有希望的候选者。此外，在虾虎鱼科进化枝的AQP11b主干分支中发现的正选择特征表明，该进化枝可能存在功能改变的情况。
