Intron loss dynamics in mammals

Abstract

We used whole-genome sequence alignments of human, mouse, rat, and dog to perform a genome-wide analysis of intron loss and gain events in over 17,000 mammalian genes. We found no evidence for intron gain and 122 cases of intron loss, most of which occurred within the rodent lineage. Majority (68%) of the deleted introns were extremely small (<150 bp), significantly smaller than average. The intron losses occurred almost exclusively within highly expressed, housekeeping genes, supporting the hypothesis that intron loss is mediated via germline recombination with spliced mRNA intermediates. This study constitutes the largest scale analysis for intron dynamics in vertebrates to date and allows us to confirm and extend several hypotheses previously based on much smaller samples. © Springer-Verlag Berlin Heidelberg 2006.