Statistics of Exon Lengths in Fungi

Abstract

The exon-intron structures of fungi genes are quite different from each other, and the evolution of such structures raises many questions. We tried to address some of these questions with an accent on methods of revealing evolutionary factors based on the analysis of gene exon-intron structures using statistical analysis. Taking whole genomes of fungi, we went through all the protein-coding genes in each chromosome separately and calculated the portion of introncontaining genes and average values of the net length of all the exons in a gene, the number of the exons, and the average length of an exon. We found striking similarities between all of these average properties of chromosomes of the same species and significant differences between properties of the chromosomes belonging to species of different divisions (Phyla) of the kingdom of Fungi. Comparing those chromosomal and genomic averages, we have developed a technique of clustering based on characteristics of the exon-intron structure. This technique of clustering separates different fungi species, grouping them according to Fungi taxonomy. The main conclusion of this article is that the statistical properties of exonintron organizations of genes are the genome-specific features preserved by evolutionary processes.