A genetic recombination map of foot-and-mouth disease virus.

Sixty ts mutants were isolated from the Pacheco strain of type O foot-and-mouth disease virus after treatment with either 5-fluorouracil or hydroxylamine. The conditions affecting recombination and assay of the ts+ recombinants were standardized. Using two ts mutants resistant to guanidine, three-factor crosses, supported by two-factor crosses, located 34 of the mutations in a linear arrangement. The recombination frequencies between certain pairs of mutations were additive. The guanidine character of the two resistant mutants mapped as a single site mutation and was located near the middle of the map.