Genetic and amber fragment maps of genes 46 and 47 of bacteriophage T4D.

We constructed genetic recombinational maps of genes 46 and 47 by using five amber mutants in gene 46, nine amber mutants in gene 47, and two-factor crosses. Two different amber fragments in gene 46 and three different amber fragments in gene 47 were detected on polyacrylamide slab gels in the presence of sodium dodecyl sulfate. The genetic maps agreed with the amber fragment maps; taken together, the data oriented all of the sites in both genes with respect to each other. Given the relative map positions of genes 46 and 47 determined genetically by Epstein et al. (Cold Spring Harbor Symp. Quant. Biol. 28:375-394, 1963), our results extend and reinforce the work of Hercules and Sauerbier (J. Virol. 12: 872-881, 1973) and that of Minner and Bernstein (J. Gen. Virol. 31:277-280, 1976), which indicated that the direction of transcription and translation of these genes if counterclockwise on the T4 genetic map (i.e., from gene 47 toward gene 46).