FIG. 4.

Southern analyses of EcoRI-digested genomic DNA of traditional and present-day commercial strains of A. bisporus hybridized to Abr1. The hybridization patterns were of three types, corresponding to different cultivar types. Lanes: 1, off-white traditional cultivars (Somycel 9.2, Somycel 76, Sinden A4, and Le Lion B62); 2, white traditional cultivars (Somycel 53, Sinden A1, Le Lion B14, and Les Miz 66); 3, present-day hybrids (Horst U1, Horst U3, Amycel 2800, Le Lion X8, Int. Spawn 643, Sylvan 100, Sylvan 608, Le Lion X20, Le Lion X22, and Sylvan 512). The molecular size markers are indicated on the right (kilobases). Homokaryotic strains H97 (single-spore isolate from the traditional off-white line Somycel 9.2) and H39 (single-spore isolate from the traditional white line Somycel 53), which were used to construct strain Horst U1, showed hybridization patterns as depicted in lanes 1 and 2, respectively.