- Communication -
| In Silico Biology 4, 0032 (2004); ©2004, Bioinformation Systems e.V. |
Distributions of exons and introns in the human genome
Meena Kishore Sakharkar1*, Vincent T.K. Chow2 and Pandjassarame Kangueane1
1 Nanyang Centre for Supercomputing and Visualisation, N3-2c-113b, 50 Nanyang Avenue, Nanyang technological University, Singapore; Phone: +65-6-790 5836, Fax: +65-6-791 1859; Email: mmeena@ntu.edu.sg
2 Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge, Singapore
* corresponding author
Edited by E. Wingender; received April 13, 2004; revised and accepted May 27, 2004; published June 16, 2004
Abstract
The human genome is revisited using exon and intron distribution profiles. The 26,564 annotated genes in the human genome (build October, 2003) contain 233,785 exons and 207,344 introns. On average, there are 8.8 exons and 7.8 introns per gene. About 80% of the exons on each chromosome are <200 bp in length. <0.01% of the introns are <20 bp in length and <10% of introns are more than 11,000 bp in length. These results suggest constraints on the splicing machinery to splice out very long or very short introns and provide insight to optimal intron length selection. Interestingly, the total length in introns and intergenic DNA on each chromosome is significantly correlated to the determined chromosome size with a coefficient of correlation r = 0.95 and r = 0.97, respectively. These results suggest their implication in genome design.
Key words: exon, intron, length, distributions, human, genome, architecture, profile, chromosome, correlation, size, non-coding DNA, gene, average, genomics, gene evolution, genome evolution, DNA, gene structure