CODON ANALYSIS OF CYANOBACTERIAL GENES

The genes from different species of cyanobacteria have been analysed f or relationships both between them and with other microbes and organel les. The codon bias indices indicate that the unicellular Synechococcu s strain shows a preferred codon usage as those of tow expressing gene s of E. coli, Agrobacterium tumefaciens and S. typhimurium, whereas th e filamentous Anabaena sp. and Fremyella diplosiphon strains show simi larity to yeast (Saccharomyces cerevisiae), Bacillus sp., B. subtilis and Streptococcus sp. In so far as the codon bias index can be related to expression levels, the data suggest tile possibility of suitable c loning hosts. The filamentous and unicellular cyanobacteria can be cle arly separated based on the codon third-position bias and also the cor relations involving codon usage. In general, correlations in codon usa ge profiles point to the filamentous strains being more related to gra m positive bacteria and eukaryotes, whereas the unicellular strains ar e more related to gram negative bacteria.