The IDB and IEDB: intron sequence and evolution databases

A non-redundant database of nuclear, protein-encoding, genomic DNA sequence s highlighting nuclear pre-mRNA introns was constructed using information c ontained in the SWISS-PROT and GenBank sequence databases.:This Intron Data Base (IDB) contains information about (i) introns (including nucleotide seq uence, location, phase, length, GC content and consensus-sequence rule viol ations), (ii) exons (including nucleotide sequence, length and GC content), (iii) protein coding regions (including amino acid sequence and length), a nd (iv) descriptive information about the source gene and organism (includi ng gene designations and species taxonomy), The Intron Evolution DataBase ( IEDB) provides a statistical analysis of the exon and intron sequences cata logued in IDB as well as data concerning intron penetration (relative numbe r of coding regions with introns), density (number of introns per kb of tot al coding sequence DNA), distribution, and consensus sequences for each spe cies present in IDB, This supplement is provided to furnish insights into t he phylogenetic distribution and evolution of introns, Both databases are e xtensively cross-referenced to the SWISS-PROT and GenBank databases. IDB cu rrently contains information on over 63 000 genes and 154 000 introns; IEDB summarizes information on over 2800 species. IDB and IEDB will be updated twice a year and are available via the internet (http://nutmeg.bio.indiana. edu/introniindex.html).