Abstract
An earlier paper presented evidence for the evolutionary conservation of certain genes in the genus Bacillus. These have now been localized in two regions of the B. subtilis chromosome. The first contains genes coding for components of the translation mechanism and includes determinants for 16,4, and 23S RNA''s as well as for streptomycin and erythromycin resistance. These are located near the origin of the chromosome. The second group includes the micrococcin resistance and bryamycin resistance markers and is located between threonine (0.27) and leucine (0.62) on the chromosome.