近日，中科院上海生命科學研究院/上海交通大學醫(yī)學院健康科學研究所孔祥銀課題組張振國等人發(fā)現(xiàn)基因重復后基因剪接信號演化特點,，以及這些變化對基因新結構形成的影響,，該成果在線發(fā)表在《基因生物學》(Genome Biology)雜志上,。
在物種進化過程中,，基因重復是經(jīng)常發(fā)生的,。那么基因重復后，基因結構是如何演化的,？張振國等人發(fā)現(xiàn)基因重復后,，早期階段外顯子剪接增強子（Exon splicing enhancers）和外顯子剪接沉默子（Exon splicing silencers）快速變化，然后逐漸飽和,?；蛑貜秃?，外顯子剪接增強子嚴重丟失,，這些改變主要與同義突變相關；剪接信號的改變同時導致基因新的剪接形式的發(fā)生,。這一發(fā)現(xiàn)有助于理解新基因結構是如何演化的,。（生物谷Bioon.com）
基因組進化研究：
GBE：哺乳動物基因組隨進化加速變小
Nature Gene：細菌基因組正在快速進化
Genome Research：胎盤基因進化造就物種特異性
Nature：新性染色體進化驅動脊椎動物新種形成
生物谷推薦原始出處：
Genome Biology 2009, 10:R120doi:10.1186/gb-2009-10-11-r120
Divergence of exonic splicing elements after gene duplication and the impact on gene structures
Zhenguo Zhang , Li Zhou , Ping Wang , Yang Liu , Xianfeng Chen , Landian Hu and Xiangyin Kong
Background
The origin of new genes and their contribution to functional novelty has been the subject of considerable interest. There has been much progress in understanding the mechanisms by which new genes originate. Here we examine a novel way that new gene structures could originate, namely through the evolution of new alternative splicing isoforms after gene duplication.
Results
We studied the divergence of exonic splicing enhancers and silencers after gene duplication and the contributions of such divergence to the generation of new splicing isoforms. We found that exonic splicing enhancers and exonic splicing silencers diverge especially fast shortly after gene duplication. About 10% and 5% of paralogous exons undergo significantly asymmetric evolution of exonic splicing enhancers and silencers, respectively. When compared to pre-duplication ancestors, we found that there is a significant overall loss of exonic splicing enhancers and the magnitude increases with the duplication age. Detailed examination reveals net gains and losses of exonic splicing enhancers and silencers in different copies and paralog clusters after gene duplication. Furthermore, we found that exonic splicing enhancer and silencer changes are mainly caused by synonymous mutations, though nonsynonymous changes also contribute. Finally, we found that exonic splicing enhancer and silencer divergence results in exon splicing state transitions (from constitutive to alternative or vice versa), and that the proportion of paralogous exon pairs with different splicing states also increases over time, consistent with previous predictions.
Conclusions
Our results suggest that exonic splicing enhancer and silencer changes after gene duplication have important roles in alternative splicing divergence and that these changes contribute to the generation of new gene structures.
