Lynch Michael, Richardson Aaron O
Department of Biology Indiana University Bloomington, Indiana 47405, USA.
Curr Opin Genet Dev. 2002 Dec;12(6):701-10. doi: 10.1016/s0959-437x(02)00360-x.
Although the widespread proliferation of introns in eukaryotic protein-coding genes remains one of the most poorly understood aspects of genomic architecture, major advances have emerged recently from large-scale genome sequencing projects and functional analyses of mRNA-processing events. Evidence supports the idea that spliceosomal introns were not only present in the stem eukaryote but diverged into at least two distinct classes very early in eukaryotic evolution. Some rough estimates of intron turnover rates are provided, and a testable hypothesis for the origin of new introns is proposed. In light of recent findings on the molecular natural history of splicing, various aspects of the phylogenetic and physical distributions of introns can now be interpreted in a theoretical framework that jointly considers the population-genetic roles of mutation, random genetic drift, and natural selection.
尽管内含子在真核生物蛋白质编码基因中的广泛扩散仍是基因组结构中最难以理解的方面之一，但最近大规模基因组测序项目和mRNA加工事件的功能分析取得了重大进展。有证据支持这样一种观点，即剪接体内含子不仅存在于主干真核生物中，而且在真核生物进化的早期就分化为至少两个不同的类别。文中提供了一些内含子周转率的粗略估计，并提出了一个关于新内含子起源的可检验假设。鉴于最近关于剪接分子自然史的发现，现在可以在一个联合考虑突变、随机遗传漂变和自然选择的群体遗传学作用的理论框架内解释内含子系统发育和物理分布的各个方面。
