Genetic Location of Certain Mutations Conferring Recombination Deficiency in Escherichia coli

Four mutations conferring recombination deficiency (recA1, recA13, rec-12, and rec-65) have been cotransduced with cysC and pheA; consequently they lie between 53 and 50 on the standard genetic map of Escherichia coli. The four mutations show different degrees of apparent dominance in transient rec(+)/rec(-) zygotes, and the degree of apparent dominance of a particular mutation was shown to be a characteristic of that mutation, not a reflection of other genetic differences in the original rec mutant strain. All four mutations map at similar distances from cysC and pheA and, despite the different degrees of apparent dominance, all may lie in the recA gene.