Wu Min, Comeron Josep M, Yoon Hwan Su, Bhattacharya Debashish
Mol Biol Evol. 2009 Feb;26(2):249-53. doi: 10.1093/molbev/msn263. Epub 2008 Nov 13.
Actin is a conserved cytoskeletal protein that is well studied in model organisms although much less is known about actin molecular evolution in taxonomically diverse algae. Here, we analyzed 107 novel partial algal actin sequences and report some unexpected results. First, monophyletic actin gene families in multiple, phylogenetically distantly related algal taxa contain two distinct clades of sequences. One of these clades contains highly conserved sequences, whereas the second has multiple members with a significantly elevated substitution rate. This rate difference is associated with an excess of synonymous substitutions, strongly suggesting that both isoforms are active. These results paint a novel picture of actin gene evolution in algae showing it to be a remarkably dynamic system with duplication, homogenization, and potential functional diversification occurring independently in distantly related lineages.
肌动蛋白是一种保守的细胞骨架蛋白，在模式生物中已得到充分研究，尽管对于分类学上多样的藻类中肌动蛋白的分子进化了解较少。在这里，我们分析了107个新的部分藻类肌动蛋白序列，并报告了一些意外的结果。首先，在多个系统发育关系较远的藻类类群中的单系肌动蛋白基因家族包含两个不同的序列分支。其中一个分支包含高度保守的序列，而另一个分支有多个成员，其替换率显著升高。这种速率差异与同义替换的过量有关，强烈表明这两种异构体都是有活性的。这些结果描绘了藻类中肌动蛋白基因进化的新图景，表明它是一个非常动态的系统，在远缘谱系中独立发生重复、同质化和潜在的功能多样化。
