CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Porto, Portugal.
Mol Biol Evol. 2012 Dec;29(12):3887-98. doi: 10.1093/molbev/mss194. Epub 2012 Jul 27.
The mechanosensory lateral line, found only in fishes and amphibians, is an important sense organ associated with aquatic life. Lateral line patterns differ among teleost, the most diverse vertebrate taxa, hypothetically in response to selective pressures from different aquatic habitats. In this article, we conduct evolutionary genomic analyses of 34 genes associated with lateral line system development in teleosts to elucidate the significance of contrasting evolutionary rates and changes in the protein coding sequences. We find that duplicated copies of these genes are preferentially retained in the teleost genomes and that episodic events of positive selection have occurred in 22 of the 30 postduplication branches. In general, teleost genes evolved at a faster rate relative to their tetrapod counterparts, and the mutation rates of 26 of the 34 genes differed among teleosts and tetrapods. We conclude that following whole genome duplication, evolutionary rates and episodic events of positive selection on the lateral line system development genes might have been one of the factors favoring the subsequent adaptive radiation of teleosts into diverse habitats. These results provide the foundation for further detailed explorations into lateral line system genes and the evolution of diverse phenotypes and adaptations.
仅在鱼类和两栖类中发现的机械感觉侧线是与水生生活相关的重要感觉器官。侧线模式在硬骨鱼类中存在差异，硬骨鱼类是最多样化的脊椎动物类群，据推测是对不同水生栖息地的选择压力的反应。在本文中，我们对 34 个与硬骨鱼类侧线系统发育相关的基因进行了进化基因组分析，以阐明对比进化率和蛋白质编码序列变化的意义。我们发现，这些基因的重复拷贝在硬骨鱼类基因组中被优先保留，并且在 30 个复制后分支中有 22 个分支发生了正选择事件。一般来说，硬骨鱼类的进化速度相对于其四足动物对应物更快，并且 34 个基因中的 26 个的突变率在硬骨鱼类和四足动物之间存在差异。我们的结论是，在全基因组复制之后，侧线系统发育基因的进化速度和正选择事件可能是促进硬骨鱼类多样化适应辐射进入不同栖息地的因素之一。这些结果为进一步深入探索侧线系统基因以及多样化表型和适应的进化提供了基础。
