Recombinants between bacteriophages T7 and T3 which productively infect F-plasmid-containing strains of Escherichia coli.

Recombinant phages between T7 and T3 have been isolated that grow well on strains of Escherichia coli that contain the F factor. One phage that has been characterized physically and genetically is predominately of the T7 genotype. Within this hybrid phage, two separate regions of T3 DNA have been located which are necessary for the phenotype of productive growth on F-containing strains. One of these, designated M1, contains the right part of gene 1 and continues through gene 1.3; the second, M2, appears to lie between gene 3 and gene 4.