Macquarie University Faculty of Business and Economics

Abstract

The research has to do with the distribution of exon lengths. In eukaryotes cells (cells that have a nuclei) the genes are in pieces. Exons are the coding part of the gene, that is, they code for proteins. Introns do not code for protein. The introns are spliced (removed) during the transcription when the mRNA is created and therefore have been considered by some to be "unintelligible" sequence that serves no purpose.

Ever since introns were discovered (in the late 1970's) there has been debate going on in relation to the evolutionary origin and current function of introns. There are two main theories; the Intron-Early Theory and the Intron-Late Theory.

The Intron-Early Theory (or the Exon Theory of Genes) proposes that the introns were used to assemble the first genes. The first genes were made of small pieces. The basic method used by evolution to make new genes was then to shuffle the exons, and that major trend of evolution was then to lose introns and fuse small exons together to make complicated exons.

The Intron-Late Theory proposes that introns were added during evolution resulting in break up previously continuous genes. The introns inserted themselves randomly into the structure of genes.

Different distributions of the exon lengths are predicted by those two theories. Preliminary analysis shows that neither of those predicted distributions give a very good fit. We suggest that a model based on a mixture of the two predicted distributions would give a better fit.