Segregation of markers in crosses to detect recombination within MAT.
The two lines represent the genomic organization of the MAT loci. The triangles represent inserts of plasmid constructs used to tag the respective mating-type loci with antibiotic resistance markers phleomycin
(phleo r ) or hygromycin B (hyg r ). Two hundred random progeny were tested for mating type, and resistance to phleomycin or hygromycin B. Mating type and markers segregated 1:1 as expected. For each cross, 20, 000 progeny were inoculated onto culture medium. A total of 72,000 viable progeny were tested for resistance to both antibiotics. A very low number of double-resistant progeny indicated severe suppression of recombination within MAT. See Lee et al. 1999