[Homology in natural cryptic plasmids of Bacillus subtilis]

Peculiarities of DNA homology in a number of cryptic plasmids isolated from soil bacillary strains and related or identical to Bacillus subtilis were studied. Fragments generated after digestion of one of these plasmids, p1414, were employed as a probe for blot hybridization with identical fragments of other plasmids. The data obtained suggest that nearly all the studied plasmids possess a common homology site that occupies a significant plasmid portion. Regions of detectable and weak homology were located throughout this site. Moreover, plasmid p1414 was shown to carry a large site that lacks homology with plasmids belonging to two groups. Eventually, one of these plasmids demonstrates complete lack of homology with the remaining plasmids.