Like many people today, Katia Koelle is fascinated by ancestry. But she's not tracing her family tree; instead, she uses sophisticated mathematics to construct genealogies for viruses like measles and flu. “It just floors me how math can reveal fundamental patterns in biology,” she says. By analyzing viruses’ genetic heritage she can track how they have evolved, how different strains are related, and how their population has risen and fallen over time. Then she can begin to untangle how the virus's environment has pushed it to evolve in certain ways, and whether evolution or environment dominated in a particular event. Katia also hopes to evolve her 18-month-old daughter's thinking about appropriate sports for women. She's taking her to the roller derby.