Roy Scott William, Irimia Manuel
Department of Biology, San Francisco State University, San Francisco, CA, USA.
Methods Mol Biol. 2014;1126:13-33. doi: 10.1007/978-1-62703-980-2_2.
The intron-exon structures of eukaryotic nuclear genomes exhibit tremendous diversity across different species. The availability of many genomes from diverse eukaryotic species now allows for the reconstruction of the evolutionary history of this diversity. Consideration of spliceosomal systems in comparative context reveals a surprising and very complex portrait: in contrast to many expectations, gene structures in early eukaryotic ancestors were highly complex and "animal or plant-like" in many of their spliceosomal structures has occurred; pronounced simplification of gene structures, splicing signals, and spliceosomal machinery occurring independently in many lineages. In addition, next-generation sequencing of transcripts has revealed that alternative splicing is more common across eukaryotes than previously thought. However, much alternative splicing in diverse eukaryotes appears to play a regulatory role: alternative splicing fulfilling the most famous role for alternative splicing-production of multiple different proteins from a single gene-appears to be much more common in animal species than in nearly any other lineage.
真核细胞核基因组的内含子-外显子结构在不同物种间呈现出巨大的多样性。如今，多种真核生物物种的众多基因组信息使得重建这种多样性的进化史成为可能。在比较的背景下对剪接体系统进行考量，会揭示出一幅令人惊讶且极为复杂的图景：与许多预期相反，早期真核生物祖先的基因结构高度复杂，并且在许多剪接体结构方面呈现出“动物或植物样”特征；在许多谱系中，基因结构、剪接信号和剪接体机制都独立发生了显著简化。此外，转录本的新一代测序表明，可变剪接在真核生物中比之前认为的更为普遍。然而，不同真核生物中的许多可变剪接似乎发挥着调控作用：可变剪接发挥其最著名的作用——从单个基因产生多种不同蛋白质——在动物物种中似乎比在几乎任何其他谱系中都更为常见。
