Simpson Alastair G B, MacQuarrie Erin K, Roger Andrew J
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Nature. 2002 Sep 19;419(6904):270. doi: 10.1038/419270a.
Spliceosomal introns, one of the hallmarks of eukaryotic genomes, were thought to have originated late in evolution and were assumed not to exist in eukaryotes that diverged early -- until the discovery of a single intron with an aberrant splice boundary in the primitive 'protozoan' Giardia. Here we describe introns from a close relative of Giardia, Carpediemonas membranifera, that have boundary sequences of the normal eukaryotic type, indicating that canonical introns are likely to have arisen very early in eukaryotic evolution.
剪接体内含子是真核生物基因组的标志之一，曾被认为是在进化后期起源的，并且假定在早期分化的真核生物中不存在——直到在原始“原生动物”贾第虫中发现了一个具有异常剪接边界的单个内含子。在此，我们描述了贾第虫的近亲——膜质 Carpiemonas 中的内含子，其具有正常真核生物类型的边界序列，这表明典型内含子可能在真核生物进化的早期就已出现。
