Generation of a database containing discordant intron positions in eukaryotic genes (MIDB)

Motivation: Intron sliding is the relocation of intron-exon boundaries over short distances and is often also referred to as intron slippage or intron migration or intron drift. We have generated a database containing discord ant intron positions in homologous genes (MIDB-Mismatched Intron DataBase). Discordant intron positions are those that are either closely located in h omologous genes (within a window of 10 nucleotides) or an intron position t hat is present in one gene but not in any of its homologs. The MIDB databas e aims at systematically collecting information about mismatched introns in the genes from GenBank and organizing it into a form useful for understand ing the genomics and dynamics of introns thereby helping understand the evo lution of genes. Results: Intron displacement or sliding is critically important for explain ing the present distribution of introns among orthologous and paralogous ge nes. MIDB allows examining of intron movements and allows mapping of intron positions from homologous proteins onto a single sequence. The database is of potential use for molecular biologists in general and for researchers w ho are interested in gene evolution and eukaryotic gene structure. Partial analysis of this database allowed us to identify a few putative cases of in tron sliding.