Dominance in Bacteriophage T4d

HIS paper describes investigations of dominance in phage T4 using conditional lethal alleles of gene 37 in mixed infections with wild type. Previous studies of gene 37 mutant alleles were carried out by EDGAR and LIELAUSIS (1965) who showed that this gene specifies a tail fiber structural component, and by BERNSTEIN, EDGAR and DENHARDT (1965) who performed recombination and complementation analyses. It is shown here that various temperature sensitive ( t s ) and amber (am) mutants of gene 37 in mixed infections with wild type display different degrees of dominance as measured by burst size. Furthermore the plaque-forming progeny of these infections are shown to be functionally and physically distinguishable from wild-type phage. The implications of these observations with respect to the nature of dominance are discussed.