Brian Charlesworth is Royal Society Research Professor at the Institute of Cell, Animal and Population Biology, University of Edinburgh, and President of the Society for the Study Evolution. His research is mainly in evolutionary genetics, applying classical and molecular genetics to the study of evolution and natural variation. He is author of Evolution in Age-Structured Populations (CUP, 2nd edn. 1994) Deborah Charlesworth is Professor in the ICABP at Edinburgh. Her research focuses on the evolution of plant breeding systems, including how they avoid inbreeding, and work on sex chromos...