On the formation of novel genes by duplication in the caenorhabditis elegans genome
On the formation of novel genes by duplication in the caenorhabditis elegans genome
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DOI：
10.1093/molbev/msj114
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发表时间：
2006-05-01
影响因子：
10.7
通讯作者：
Lynch, M
中科院分区：
文献类型：
--
作者：
Katju, V;Lynch, M
基因复制被认为在新基因的形成中发挥着最重要的作用。基因复制的规范模型假设新基因以两步方式出现，即（1）基因的完全复制，然后（2）一个或两个拷贝中突变的逐渐积累，导致功能改变。此前已证明，秀丽隐杆线虫中超过 50% 的新生复制品在复制对的一个或两个成员中具有独特的外显子，这表明许多复制品在功能上与出生时的祖先副本并不相同。部分基因重复和嵌合基因重复都有助于新基因的形成。对于嵌合复制，独特外显子的基因组来源是多种多样的，包括基因和基因间区域以及重复元件。这些源自部分和嵌合复制的新基因与源自祖先基因的完全复制的拷贝同样可能具有转录活性。祖先拷贝中的重复断点均匀分布在基因组中，排除了任何将它们限制为特定类型序列（例如内含子）的机制的作用。最后，内含子丢失和增益都有助于两个拷贝之间内含子的差异分布。
Gene duplication is thought to play the singular most important role in the formation of novel genes. The canonical model of gene duplication postulates that novel genes arise in a two-step fashion, namely, (1) the complete duplication of a gene followed by (2) the gradual accumulation of mutations in one or both copies leading to an altered function. It was previously demonstrated that more than 50% of newborn duplicates in Caenorhabditis elegans had unique exons in one or both members of a duplicate pair, indicating that many duplicates are not functionally identical to the progenitor copy at birth. Both partial and chimeric gene duplications contribute to the formation of novel genes. For chimeric duplications, the genomic sources of unique exons are diverse, including genic and intergenic regions, as well as repetitive elements. These novel genes derived from partial and chimeric duplications are equally likely to be transcriptionally active as copies derived from complete duplications of the ancestral gene. Duplication breakpoints in the ancestral copies are uniformly distributed in the genome, ruling out the role of any mechanism that restricts them to a particular type of sequence such as introns. Finally, both intron loss and gain contribute to the differential distribution of introns between two copies.