Figure 5.

Numbers of remaining CUP1 repeats associated with loss of URA3 on the W303-1A-derived chromosome VIII homolog of YZ104; the starting strain had 18 repeats on this homolog. We isolated 33 independent spontaneous 5-FOA^R Hyg^R Gen^R Can^S derivatives. CUP1 copy numbers were determined by measuring the size of CUP1 cluster by Southern analysis of EcoRI-digested genomic DNA. A hybridization probe specific for the W303-1A type of CUP1 repeat was used. 5-fluoroorotic acid; Can, L-canavanine; Gen, geneticin; Hyg, hygromycin B; ^R, resistant; ^S, sensitive.