Nurtdinov Ramil N, Mironov Andrey A, Gelfand Mikhail S
Departament of Bioengineering and Bioinformatics, M V Lomonosov Moscow State University, Moscow, Russia.
BMC Evol Biol. 2009 Jun 26;9:142. doi: 10.1186/1471-2148-9-142.
Alternative splicing is an important mechanism for generating functional and evolutionary diversity of proteins in eukaryotes. Here, we studied the frequency and functionality of recently gained, rodent-specific alternative exons.
We projected the data about alternative splicing of mouse genes to the rat, human, and dog genomes, and identified exons conserved in the rat genome, but missing in more distant genomes. We estimated the frequency of rodent-specific exons while controlling for possible residual conservation of spurious exons. The frequency of rodent-specific exons is higher among predominantly skipped exons and exons disrupting the reading frame. Separation of all genes by the rate of sequence evolution and by gene families has demonstrated that rodent-specific cassette exons are more frequent in rapidly evolving genes and in rodent-specific paralogs.
Thus we demonstrated that recently gained exons tend to occur in fast-evolving genes, and their inclusion rate tends to be lower than that of older exons. This agrees with the theory that gain of alternative exons is one of the major mechanisms of gene evolution.
可变剪接是真核生物中产生蛋白质功能和进化多样性的重要机制。在此，我们研究了近期获得的啮齿动物特异性可变外显子的频率和功能。
我们将小鼠基因可变剪接的数据投射到大鼠、人类和狗的基因组上，鉴定出在大鼠基因组中保守但在更远缘基因组中缺失的外显子。我们在控制假外显子可能的残留保守性的同时，估计了啮齿动物特异性外显子的频率。在主要被跳过的外显子和破坏阅读框的外显子中，啮齿动物特异性外显子的频率更高。通过序列进化速率和基因家族对所有基因进行分类，结果表明，啮齿动物特异性盒式外显子在快速进化的基因和啮齿动物特异性旁系同源物中更为常见。
因此，我们证明了近期获得的外显子倾向于出现在快速进化的基因中，并且它们的包含率往往低于较古老外显子的包含率。这与可变外显子的获得是基因进化的主要机制之一这一理论相符。
