Knowledge about genetics is essential to build a society capable of participating in socioscientific and ethical debates. However, this subject remains difficult for students, making it necessary to develop new educational strategies, such as gamification. Thus, two main objectives are established in this work: (a) to design and evaluate BreakoutEDU, a gamified activity to improve understanding of the content of gene expression; and (b) to study the emotions triggered by this activity among students. Using questionnaires and observation templates, the implementation of BreakoutEDU is evaluated in two groups of first-year high school students (15 and 10 students). The results are analyzed qualitatively and quantitatively. Bearing in mind the limitations of this study, it is concluded that the designed BreakoutEDU could support gamification as a good strategy to contextualize and approach the abstract content of gene expression. Moreover, the activity could maintain a balance between time, difficulty and students' skills, encourage teamwork and trigger mainly positive emotions.