FIG. 3.

Southern blot analysis of strains transformed with the C3-2 linear fragment. Genomic DNAs were digested by XbaI, electrophoresed on a 0.8% agarose gel, transferred to a nitrocellulose membrane, and hybridized with a ³²P-labeled 663-bp PCR-amplified fragment of pksN spanning the two XbaI sites surrounding the I₄ mutation (Fig. 1). Lane 1, [a*₅₈] (I₄⁺ allele); lane 2, [a₁s₁I₄mod] (mutated allele); lanes 3 and 4, transformants E11 and E53, respectively, with restored I₄⁺ perithecial red pigmentation.