STUDY OF HOMOLOGY IN BACILLUS-SUBTILIS CR YPTIC PLASMIDS

Peculiarities of DNA homology in a number of cryptic plasmids isolated from soil bacillar strains and related or identical to Bacillus subti lis 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 oc cupies a significant plasmid portion. Regions of detectable and weak h omology were located throughout this site. Moreover, plasmid p1414 was shown to carry a large site that lacks homology with plasmids belongi ng to two groups. Eventually, one of these plasmids demonstrates compl ete lack of homology with the remaining plasmids.