Alternative splicing landscape of the Drosophila melanogaster genome

Alternative splicing (AS) intensity (isoform number per gene) was studied as dependent on the gene size for various regions of the Drosophila melanogaster genome. The AS intensity of long transcripts from regions with a low gene density proved to be significantly higher than for regions with a high gene density. An opposite pattern was observed for small genes. The intron density distribution was approximated using the Γ distributions for regions with a high or low gene density. Statistical comparisons of the γ distributions confirmed a lower coefficient λ for regions with a low gene density (i.e., the average intron density was higher). Based on these data, relaxed evolution of the exon-intron structure was assumed for regions with a low gene density.