The universality of the genetic code has allowed DNA isolated from a specific organism to be transferred and incorporated in another organism, transforming bacterial, yeast, plant, and animal cells. This transformation ability is the essence of recombinant DNA technology. Recombinant DNA has been used to make medically useful proteins that would otherwise have been difficult to obtain in necessary amounts, or to engineer plants to be herbicide or insect resistant. The following activity, which focuses on mapping DNA using restriction enzymes, can help students gain a better understanding about DNA and its manipulation. The activity is designed for high school and college biology students.