This lab focuses on a vitamin-enriched strain of baker’s yeast that produces β-carotene, the nutrient that is converted to Vitamin A in the body. These genetically engineered yeast turn bright orange when they make β-carotene. Unexpectedly, not all the yeast are orange. Sometimes they grow as red, yellow or white colonies. The Golden Bread labs investigate this instability in the yeast, and challenge your students to improve the strain’s performance. Lab activities that include PCR, yeast transformation, and codon shuffling and quantitative analysis of data.