Construction of the genetic map of the polyoma genome

Seven early mutants, three late mutants, and one plaque morphology mutant of polyoma have been mapped by marker rescue using wild-type restriction endonuclease fragments. The early mutants map between 1.0 and 26.4 units from the Eco RI site, a region previously shown to correspond to the 3'-OH termainal half of "early" RNA (Kamen et al., 1974). The late mutants as well as the plaque morphology mutant map between 26.6 and 45.4 map units, a region previously shown to correspond to the 3'-OH terminal half of "late" RNA (Kamen et al., 1974). Analysis of the genotype of rescued virus demonstrated that the modification of the mutant DNA during marker rescue was limited to the region of the genome covered by the wild-type restriction endonuclease fragment tested.