Karla Kirkegaard, Ph.D. is Professor and former Chair of the Department of Microbiology and Immunology at Stanford University School of Medicine. She earned her undergraduate degree in genetics from the University of California, Berkeley, where her studies ranged from theater and literature to genetics and biochemistry. Following her Ph.D. research in biochemistry and molecular biology at Harvard University, her postdoctoral research at Massachusetts Institute of Technology established that recombination between viruses with RNA as their genetic material occurs by copy-choice, a completely different mechanism than the breaking-and-rejoining used to recombine DNA. Kirkegaard combined her interests in biochemistry, cell biology, and genetics in the study of RNA virology, using poliovirus and other positive-strand RNA viruses to understand the cell biology of viral infections and the genetics of viral variability. Since her move to Stanford University School of Medicine in 1996, her interests have focused increasingly on the impact of basic science discoveries on the transmission of viruses in infected hosts. She continues to be fascinated by the mechanisms, so extraordinary as to be nearly fanciful, that viruses display. Her current research focuses on understanding the apparent inevitability of viral evolution well enough to thwart it.