Genome organization is not conserved between Bacillus cereus and Bacillus subtilis

The opportunistic pathogen Bacillus cereus is the genetically stable member of a group of closely related bacteria including the insect pathogen Bacil lus thuringiensis and the mammalian pathogen Bacillus anthracis. Physical m aps of B. cereus and B. thuringiensis strains show considerable variations in discrete parts of the chromosome, suggesting that certain genome regions are more prone to rearrangements. B. cereus belongs to the same subgroup o f Bacillus species as Bacillus subtilis, by both phenotypic and rRNA sequen ce classification. The analysis of 80 kb of genome sequence sampled from di fferent regions of the B. cereus ATCC 10987 chromosome is reported. Analysi s of the sequence and comparison of the localization of the putative genes with that of B. subtilis orthologues show the following: (1) gene organizat ion is not conserved between B. cereus and B. subtilis; (2) several putativ e genes are more closely related to genes from other bacteria and archaea t han to B. subtilis, or may be absent in B. subtilis 168; (3) B. cereus cont ains a 155 bp repetitive sequence that is not present in B. subtilis. By hy bridization, this repeat is present in all B. cereus and B. thuringiensis s trains so far investigated.