The selection of plasmids in yeast is based on the use of auxotrophic mutant strains that cannot grow without a specific media component (an amino acid, purine or pyrimidine). Transformation with a plasmid containing the mutated gene enables the transformant to grow on a medium lacking the required component. Sigma′s Yeast Synthetic Drop-Out Media Supplements create a richer medium for better yield and growth rate, and increase the probability of successful transformations when screening libraries or performing gene knock-outs.

Mixtures of amino acids and other nutrients to be added to Yeast Nitrogen Base Without Amino Acids.