Tittiger C, Whyard S, Walker V K
Department of Biology, Queen's University, Kingston, Ontario, Canada.
Nature. 1993 Feb 4;361(6411):470-2. doi: 10.1038/361470a0.
The origin and function of introns in eukaryotic genes has provoked considerable debate since their discovery in 1977. Central to this issue are studies on the highly conserved enzyme, triosephosphate isomerase (TPI, EC 5.3.1.1). The 'introns early' argument suggests that introns are as old as the genes themselves and that the apparent correlation of many of the intron sites in plant, animal and fungal TPI genes with the boundaries of modules is evidence of the assembly of ancient proteins by exon shuffling. In contrast, the 'introns late' view holds that ancient genomes contained few if any introns; introns were inserted into pre-existing genes during the last billion years. We have found that the TPI gene from the mosquito, Culex tarsalis, contains an intron in a unique position that was predicted by W. Gilbert and the exon shuffling hypothesis.
自1977年发现以来，真核基因中内含子的起源和功能引发了诸多争论。高度保守的酶——磷酸丙糖异构酶（TPI，EC 5.3.1.1）的研究是这个问题的核心。“内含子早现”观点认为，内含子与基因本身一样古老，而且植物、动物和真菌TPI基因中许多内含子位点与模块边界的明显相关性是外显子重排组装古老蛋白质的证据。相反，“内含子晚现”观点认为，古代基因组中即使有内含子也很少；内含子是在过去十亿年中插入到已有基因中的。我们发现，来自库蚊的TPI基因在一个独特位置含有一个内含子，这是由W. 吉尔伯特和外显子重排假说预测到的。
