REP code: defining bacterial identity in extragenic space

Summary Through the analysis of 57 bacterial genomes we have detected repetitive extragenic palindromic DNA sequences (REPs) in 11 species. For a sequence to be considered as REP, the following criteria should be met: (i) It should be extragenic, (ii) palindromic, (iii) of a length between 21 and 65 bases and (iv) should constitute more than 0.5% of the total extragenic space. Species‐specific REPs have been found in human pathogens such as Escherichia coli , Salmonella enterica , Neisseria meningitidis , Mycobacterium tuberculosis , Rickettsia conorii and Pseudomonas aeruginosa , the plant pathogen Agrobacterium tumefaciens and the soil bacteria Deinococcus radiodurans , Pseudomonas putida and Sinorhizobium meliloti .