Nonselective URA3 Colony-Color Assay in Yeast ode 1 or ade2 Mutants

摘要

Phenotypes of the yeast Saccha-romyces cerevisiae are normally assayed with synthetic, minimal media lacking one or more amino acids. For some markers, such as those in the adenine biosynthetic pathway, pheno-types can be distinguished by colony coloron nonselective (rich) media. Thus, ade1 and ade2 mutants produce red or pink colonies, while wild-type yeast colonies are white. Color markers have advantages over typical selectable markers. Color markers can be assayed in a single step, whereas typical markers are usually assayed by replica plating to media lacking a particular metabolite. Although single-step selection is possible for most markers, selective strategies may prevent certain products from being detected, and this may compromise experimental analyses. Thus, screening color phenotypes on nonselective media facilitates more complete product analysis for some types of experiments, such as those in which mixed (sectored) colonies may arise.