Conjugational Complementation Analysis of Transfer-Deficient Mutants of F lac in Escherichia coli

Abstract

A series of 102 transfer-deficient ( tra − ) mutants of F lac (84 of which have been previously described) were classified as carrying frameshift, amber, ochre, UGA, and nonsuppressible mutations. Techniques were evolved for using cultures of F prime strains as efficient recipients in matings, for measuring the number of (F′/F′) heterozygote cells in transient populations, and for measuring complementation between different F lac tra − mutants. These techniques were used to define nine tra cistrons and to assign most of the tra − mutations to one or other of these.