Nucleic Acids Research Advance Access originally published online on March 26, 2008
Nucleic Acids Research 2008 36(8):2756-2763; doi:10.1093/nar/gkn086
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nucleic Acids Research, 2008, Vol. 36, No. 8 2756-2763
© 2008 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Genomics |
Spontaneous symmetry breaking in genome evolution
1Department of Chemistry, Purdue University, 560 Oval drive, Box 202 and 2Department of Biological Sciences, Lilly Hall of Life Sciences 915 W. State Street, Purdue University, West Lafayette, IN, 47907, USA
*To whom correspondence should be addressed. Tel: +301 435 9034; Fax: 301 480 0028; Email: yryabov{at}mail.nih.gov
Received November 14, 2007. Revised February 7, 2008. Accepted February 11, 2008.
The quest for evolutionary mechanisms providing separation between the coding (exons) and noncoding (introns) parts of genomic DNA remains an important focus of genetics. This work combines an analysis of the most recent achievements of genomics and fundamental concepts of random processes to provide a novel point of view on genome evolution. Exon sizes in sequenced genomes show a lognormal distribution typical of a random Kolmogoroff fractioning process. This implies that the process of intron incretion may be independent of exon size, and therefore could be dependent on intron–exon boundaries. All genomes examined have two distinctive classes of exons, each with different evolutionary histories. In the framework proposed in this article, these two classes of exons can be derived from a hypothetical ancestral genome by (spontaneous) symmetry breaking. We note that one of these exon classes comprises mostly alternatively spliced exons.