Sean Carroll explores the origin of novelty – one of the central questions of evolutionary biology. Carroll and his team generally seek to understand the relative contributions of different genetic mechanisms, such as gene co-option, gene duplication and loss, and regulatory and protein sequence changes, to the evolution of different kinds of traits. Their research has traditionally focused on the evolution of morphological traits in animals, which is driven primarily by changes in modular enhancers of developmentally regulated genes. More recently, the team is investigating biochemical novelties such as the origin and evolution of snake venom toxins.