Not born equal: Increased rate asymmetry in relocated and retrotransposed rodent gene duplicates
Not born equal: Increased rate asymmetry in relocated and retrotransposed rodent gene duplicates
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DOI：
10.1093/molbev/msl199
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发表时间：
2007-03-01
影响因子：
10.7
通讯作者：
Wolfe, Kenneth H.
中科院分区：
文献类型：
--
作者：
Cusack, Brian P.;Wolfe, Kenneth H.
重复的基因经常以不同的速度进化。这种不对称是自然选择区分两个拷贝的能力的证据，使它们受到不同程度的净化选择，甚至允许一个或两个拷贝的适应性进化。然而，如果基因复制产生了一对最初相同的蛋白质编码序列，这就提出了选择如何区分这两个拷贝的问题。在这里，我们研究了啮齿类动物最近复制的基因的不对称序列分化，并将其与这种不对称的两个可能来源联系起来：作为复制结果的基因重新定位和作为基因复制机制的反转录转位。我们发现，大多数被重新定位的年轻啮齿动物的副本是通过反转录转位产生的。其中一个拷贝被重新定位（通过反转录转位或基于dna的复制）的基因对的速率不对称程度大于由局部基于dna的复制事件形成的基因对。此外，通过考虑远端重复的转位方向，我们发现逆转录基因相对于其静态相似物具有加速蛋白质进化的一致趋势，而基于dna的转位则没有这种趋势。最后，我们证明了逆转录基因更快的序列进化与它们的表达模式的深刻改变有关，这种改变是由逆转录转位引起的。
Duplicated genes frequently evolve at different rates. This asymmetry is evidence of natural selection's ability to discriminate between the 2 copies, subjecting them to different levels of purifying selection or even permitting adaptive evolution of one or both copies. However, if gene duplication creates pairs of protein-coding sequences that are initially identical, this raises the question of how selection tells the 2 copies apart. Here, we investigated asymmetric sequence divergence of recently duplicated genes in rodents and related this to 2 possible sources of such asymmetry: gene relocation as a consequence of duplication and retrotransposition as a mechanism of gene duplication. We found that most young rodent duplicates that have been relocated were created by retrotransposition. The degree of rate asymmetry in gene pairs where one copy has been relocated (either by retrotransposition or DNA-based duplication) is greater than in pairs formed by local DNA-based duplication events. Furthermore, by considering the direction of transposition for distant duplicates, we found a consistent tendency for retrogenes to undergo accelerated protein evolution relative to their static paralogs, whereas DNA-based transpositions showed no such tendency. Finally, we demonstrate that the faster sequence evolution of retrogenes correlates with the profound alteration of their expression pattern that is precipitated by retrotransposition.