The Distribution Profiles of GC Content surrounding the Translation Initiation Site in Different Species

Masahiko MIZUNO (

Institute for Chemical Research, Kyoto University


We analyze the distribution of GC content around the translation initiation site in genomic DNA sequences of different species using a DNA data bank, GenBank (release 72, 73). We select the data sets of entries with no homologous sequences whose homology is more than certain thresholds in each species. A window length of 100 bases is shifted each time by 50 bases along the nucleotide sequences of these entries from the -500 base position to the +500 base position. (The first nucleotide at the initiator codon is designated +1, with positive and negative integers proceeding 3' and 5', respectively.) The average of GC content in each region surrounding the translation initiation site is calculated from 10 and more windows located at the same region in the same species. The comparison of the GC content patterns of different species suggests that the distribution profiles of GC content around the translation initiation site dcpend on the kind of organism groups to which the species belong and that these GC content profiles are characteristic of organism groups.