Zum Paarungsmechanismus von Bakteriophagen

Abstract

Results of crosses of T1 phage with three symmetrically and closely linked markers gained from single burst experiments are evaluated statistically. Under two assumptions A) every elementary act of mating producing only one type of recombinant, B) every act producing a pair of two different recombinant types, expected percentages of mixed bursts are calculated, which show no, only one and both types of this recombinant pair. The following three pairs of recombinants were considered as possibly having arisen synchronously: 1. the reciprocal types: Abc and aBC, 2. the „transverse“ types: ABc and Abc, 3. the „reflected“ types ABc and aBC. Experimental data are compared with the results of the above mathematical treatment, giving evidence of all recombinants arising in independent elementary acts according to assumption A. Four existing models of phage replication and pairing are discussed. A synthesis of the population genetics of the Delbrück-Visconti- theory and the switching-mechanism of the Sturtevant- model is suggested to explain the results. In addition this idea accounts at least qualitatively for the occurence of heterozygotes and multiple reactivation and is very similar to the Levinthal- model of pairing, which is also in agreement with the established data.