Phenotypic instability in a tif-1 mutant of Escherichia coli. II. Recessiveness of the tif-1 mutation.

Merodiploids of the type tif-1/F'tif+, constructed in E. coli K12 strain T44(lambda), show that the tif-1 mutation is recessive with respect to induction of phage lambda and thermolability. An additional manifestation of tif-1 expression is increased tolerance to low levels of streptomycin (SM) and chloramphenicol (CM) and this, too, is abolished in the merodiploids.