Genetic mapping of a group of temperature-sensitive dna initiation mutants in Bacillus subtilis

Recombination frequencies among temperature-sensitive dna mutants from various laboratories were analyzed, and eleven dna mutants were found to be closely linked. They are classified as group B dna mutants, since these are closely linked with dnaB19, originally isolated and approximately mapped near leuA8 by KARAMATA and GROSS (1970). However, the dnaB19 mutation itself has relatively high recombination frequencies with the other mutations, thus, we propose to subdivide the dnaB group into two subgroups--dnaBI, including ten mutants (dna-1, dna-3, dna-5, dna-17, dna-27, dna-51, dna-60, dna-62, dna-103 and dna-134) and dnaBII, including dnaB19. The map order of dnaB and markers in the vicinity was determined to be argA-citH-citC-phoP-PhoR-polA-dnaBI-dnaBII-citF-leuA-pheA.