Abstract
Defective phages φ170dg recombined with the related phages λ, 434, 82 or φ80 when one of the related phages is superinfected to a defective lysogenic strain φ170dg, or when a doubly lysogenic strain (φ170dg)(φ) was induced with UV irradiation. The resulted particles having the immune specificity of φ170 always have the host range of the colysogenizing phage, that is, φ170hy type.
When a defective lysogenic strain was spotted on a hetero-immune indicator, the recombinant type phage is responsible to form a lytic zone. The recombination was also confirmed by using various λsus mutants. In lysates prepared from doubly lysogenic strain (φ170dg)(λsus) contained both φ170hy and φ170hysus, or φ170hysus alone according to the sus markers used. From the recovery of the sus markers among φ170hy particles, we may assume the defective region of φ170dg.
Defective region of a given φ170dg was also assumed by complementation test, using Pm- (φ170dg) and various λsus mutants. From the results obtained by these methods, similarity of arrangement of genetic markers on the chromosome of λ and φ170 was assumed.
