Recombination between guanidine-resistant and dextran sulfate-resistant mutants of type 1 poliovirus.

Mixed infection of monkey kidney cells with two mutants of the LSc2ab strain of poliovirus, one resistant to guanidine and the other resistant to both dextran sulfate and 2-(alpha-hydroxybenzyl)-benzimidazole (HBB), yielded progeny in which the number of gua(r)dex(r) particles exceeded by a factor of 7 to 10 the expected number of similar particles occurring through spontaneous mutation; recombination would explain the fairly high excess of doubly mutant particles that was obtained. Scoring of HBB resistance in 50 gua(r)dex(r) clones suggested that, during recombination, resistance to dextran sulfate is not associated with HBB resistance.