This "clicker case" focuses on the use of molecular biology concepts and techniques to protect the property of a fictional bread company. Students will address questions as to how one can "mark" a yeast strain by embedding a particular DNA sequence into its genome and then examine the claims of a competing company that is allegedly using its own bread-making yeast to create a similar product. The focus of the case is on the experimental steps required to construct the desired yeast strain and then later extract a hidden genomic message. While the class is guided through the process, students will also have opportunities to independently design their own experiments, discuss the merits of different experimental strategies, and analyze data. The case is intended to generate active discussion between students and their instructor and to illustrate the real-world implications of molecular biology in today's society.