Abstract

In his widely cited book ‘Evolution by Gene Dupli-cation’, Susumu Ohno was one of the first to suggest that gene duplication might have been more important in shaping the evolution of biological novelty and complexity than natural selection acting on point muta-tions1. Many now share this view. In particular, large-scale gene duplication events might explain major leaps in evolution or adaptive radiations of species. For example, had large-scale gene duplication events in early vertebrate evolution2–7 not occurred, vertebrates as we know them today might not have existed1,8,9. Moreover, genome duplication is probably the main way in which SYMPATRIC SPECIATION and adaptation occurs in plants, owing to its large-scale effects on gene regulation and developmental processes10,11. Similarly, in ray-finne