The Population Genetics of Somatic Mutation in Plants

We hypothesize that somatic mutations may be the cause of variability among branches within individual trees, and that this variation is sufficient to deter herbivores. We discuss two single-locus genetic models of somatic mutation and consider how the organization of meristems affects somatic mutation rates. The models reveal that somatic mutation may be an important source of variation not only within trees but also within tree populations. If mutated buds have a selective advantage, the process may be even more important. Conditions under which somatic mutations may deter herbivores are restrictive, however, and finding variation at a single locus on an individual tree is highly improbable.