RAD-seq genotyping of galactose-tolerant progeny from a backcross between disomic strain YPG3121 (chromosome XIII disome) and parent YO795

For Gal7-deletion yeast strains, growth on galactose-containing medium is lethal. We crossed 2 highly diverged S. cerevisiae strains with Gal7-deletions and selected the rare (~1/1000) progeny capable of growth on galactose. These strains were genotyped and karyotyped using RAD-seq (Restriction Associated DNA sequencing) with the MboI and MfeI restriction enzymes. A substantial minority of the gal-resistant progeny were disomic for chromosome XIII. We backcrossed 2 of these strains to the parents (one to each parent, based on mating type) to examine the importance of the aneuploidy in the gal-resistant phenotype.