[Suppression of DNA-ligase deficiency and selective breeding of mutants and recombinants of T4 phage with phenotype rII].

: A number of methods which greatly simplify the introduction of frame shift mutations in the limited segment of the phage T4 rII genes were developed for studying genetical recombination between closely linked markers. These methods enable to construct multiple rII mutants with relatively small expenditure of labour. Suppression of gene 30 deficiency by rII mutations has been studied for a variety of conditions. The results obtained indicate that rIIB polypeptide is involved in two different activities: rIIB region which is dispensable for growth on lambda-lysogenic Escherichia coli strains behaves as indispensable in phenomenon of suppression of ligase deficiency.