Genetic transfer of guanidine resistance from type 2 to type 1 poliovirus

Summary Following mixed infection of monkey kidney cells with a guanidine-sensitive clonal derivative of the attenuated LSc2ab type 1 poliovirus strain and with a guanidine-resistant clonal derivative of the MEF₁ type 2 strain, the frequency of guanidine-resistant type 1 particles was found to be increased in the progeny. The frequency of these particles was almost 4 times higher than that of spontaneous mutants in the progeny of the self cross. This difference being statistically significant it is considered to be an argument in favour to the occurrence of recombination between the two serologically unrelated poliovirus strains.Investigation of a group of unselected genetic markers in the type 1 guanidine-resistant clonal strains derived from the progeny of mixed infection showed that transfer of guanidine resistance from the type 2 parental strain was not associated with the transfer of any other character of this strain.