Test of the stability of the 5-FOA resistant uracil prototroph phenotype.

PB3636, PB3637, PB3638 and PB3839 are 5-FOA resistant prototrophic cells isolated in the M background, while PB3643, PB3644, PB3645 & PB3646 are 5-FOA resistant prototrophic cells isolated in the P background. PB1623 is a wild-type prototrophic strain in the M background and ura5 is a 5-FOA resistant mutant in ura5. Colonies plated on rich medium (YES) were replica plated onto YES, MM and 5-FOA, and cells growing on any selective medium were counted. (XLSX)