Archiv der Royal Society. Dean has made outstanding contributions in the study of developmental timing in plants. Her work has revealed the mechanism by which plants remember they have experienced winter, demonstrated novel RNA processing mechanisms controlling flowering and determined the molecular basis of natural variation in Arabidopsis flowering time. Her discoveries have broad significance in the fields of epigenetics, post-transcriptional regulation and molecular evolution. Dean has also made a massive contribution to the development of Arabidopsis as a model, establishing resources for genetic mapping and insertional mutagenesis, and providing physical maps that underpinned the sequencing of the genome.