School of Life Sciences, East China Normal University, Shanghai 200062, China.
Curr Biol. 2010 Jan 26;20(2):R53-4. doi: 10.1016/j.cub.2009.11.058.
Cases of convergent evolution - where different lineages have evolved similar traits independently - are common and have proven central to our understanding of selection. Yet convincing examples of adaptive convergence at the sequence level are exceptionally rare [1]. The motor protein Prestin is expressed in mammalian outer hair cells (OHCs) and is thought to confer high frequency sensitivity and selectivity in the mammalian auditory system [2]. We previously reported that the Prestin gene has undergone sequence convergence among unrelated lineages of echolocating bat [3]. Here we report that this gene has also undergone convergent amino acid substitutions in echolocating dolphins, which group with echolocating bats in a phylogenetic tree of Prestin. Furthermore, we find evidence that these changes were driven by natural selection.
趋同进化的案例——不同谱系独立进化出相似特征——很常见，并且已被证明是我们理解选择的核心。然而，在序列水平上令人信服的适应性趋同的例子非常罕见[1]。运动蛋白 Prestin 在哺乳动物的外毛细胞（OHC）中表达，被认为赋予了哺乳动物听觉系统的高频敏感性和选择性[2]。我们之前报道过 Prestin 基因在回声定位蝙蝠的无关谱系中经历了序列趋同[3]。在这里，我们报告说，这个基因在回声定位海豚中也发生了趋同的氨基酸替换，在 Prestin 的系统发育树中，回声定位海豚与回声定位蝙蝠聚在一起。此外，我们发现这些变化是由自然选择驱动的证据。
