Figure 1.—

Characterization of Ty1 restriction mutants. Ninety-one mutants (1.9%) were identified from 4639 MATα deletion strains, on the basis of an increased level of His⁺ papillation mediated by a chromosomal Ty1 element containing the retrotransposon mobility marker, his3-AI. Thirty-three mutants were chosen for further analyses after considering the function of the deleted gene and the level of Ty1his3-AI mobility, 20 mutants were identified in other screens for Ty1 mobility, and 38 mutants remain to be characterized.