Just as paleontologists have fossils and archeologists have relics, biomedical researchers have DNA to help them study the past and better understand the present. Studying changes as well as similarities in DNA sequences reveals how organisms change, or evolve, over time. In this issue, we highlight how the concept of evolution undergirds our understanding of antibiotic resistance, the rise of certain diseases, and the way genes are regulated. We also join the worldwide celebration of the 200th birthday of Charles Darwin, whose work paved the way for so much of today’s biomedical research. Image courtesy of science illustrator Emily Harrington of the University of California, Santa Cruz.