Development of the genetic cross. A) Schematic representation of the genetic cross between type 10 VAND and type 2 ME49 strains. Recombinant progeny were isolated either using dual drug selection or genotyping using eight RFLP makers located on separate chromosomes. B) Confirmation of recombinant progenies by PCR-RFLP markers. Markers are listed to the left, and restriction enzymes used in the digest to the right. V, VAND SNFR; M, ME49 FUDRR, clone names are indicated above the gel. –Ve, negative control.