Phase distribution of spliceosomal introns: implications for intron originReportar como inadecuado

Phase distribution of spliceosomal introns: implications for intron origin - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Evolutionary Biology

, 6:69

First Online: 08 September 2006Received: 08 August 2006Accepted: 08 September 2006


BackgroundThe origin of spliceosomal introns is the central subject of the introns-early versus introns-late debate. The distribution of intron phases is non-uniform, with an excess of phase-0 introns. Introns-early explains this by speculating that a fraction of present-day introns were present between minigenes in the progenote and therefore must lie in phase-0. In contrast, introns-late predicts that the nonuniformity of intron phase distribution reflects the nonrandomness of intron insertions.

ResultsIn this paper, we tested the two theories using analyses of intron phase distribution. We inferred the evolution of intron phase distribution from a dataset of 684 gene orthologs from seven eukaryotes using a maximum likelihood method. We also tested whether the observed intron phase distributions from 10 eukaryotes can be explained by intron insertions on a genome-wide scale. In contrast to the prediction of introns-early, the inferred evolution of intron phase distribution showed that the proportion of phase-0 introns increased over evolution. Consistent with introns-late, the observed intron phase distributions matched those predicted by an intron insertion model quite well.

ConclusionOur results strongly support the introns-late hypothesis of the origin of spliceosomal introns.

AbbreviationsRPribosomal protein

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2148-6-69 contains supplementary material, which is available to authorized users.

Download fulltext PDF

Autor: Hung D Nguyen - Maki Yoshihama - Naoya Kenmochi


Documentos relacionados