TEMPO AND MODE IN PLANT BREEDING SYSTEM EVOLUTION
Article first published online: 2 AUG 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 66, Issue 12, pages 3701–3709, December 2012
How to Cite
Goldberg, E. E. and Igić, B. (2012), TEMPO AND MODE IN PLANT BREEDING SYSTEM EVOLUTION. Evolution, 66: 3701–3709. doi: 10.1111/j.1558-5646.2012.01730.x
- Issue published online: 3 DEC 2012
- Article first published online: 2 AUG 2012
- Accepted manuscript online: 2 JUL 2012 11:40AM EST
- Received April 5, 2012 Accepted June 5, 2012
- Comparative methods;
- Dollo’s law;
Classic questions about trait evolution—including the directionality of character change and its interactions with lineage diversification—intersect in the study of plant breeding systems. Transitions from self-incompatibility to self-compatibility are frequent, and they may proceed within a species (“anagenetic” mode of breeding system change) or in conjunction with speciation events (“cladogenetic” mode of change). We apply a recently developed phylogenetic model to the nightshade family Solanaceae, quantifying the relative contributions of these two modes of evolution along with the tempo of breeding system change, speciation, and extinction. We find that self-incompatibility, a genetic mechanism that prevents self-fertilization, is lost largely by the cladogenetic mode. Self-compatible species are thus more likely to arise from the isolation of a newly self-compatible population than from species-wide fixation of self-compatible mutants. Shared polymorphism at the locus that governs self-incompatibility shows it to be ancestral and not regained within this family. We demonstrate that failing to account for cladogenetic character change misleads phylogenetic tests of evolutionary irreversibility, both for breeding system in Solanaceae and on simulated trees.