Plant secondary metabolite polymorphisms and the extended chemical phenotype

As it was originally proposed, the extended phenotype complised 'all effects of a gene upon the world' (Dawkins, 1989) and pmtrayed how the effects of a gene borne by an organism influenced its biotic and abiotic environments. The consideration of indirect genetic effects, in which an organism's phenotype becomes part of the selective environment of conspecifics (Wolf et al., 1998), was developed rigorously in the population genetics context and the concept subsequently extended to include effects on heterospecifics (Whitham et al., 2003). The extended phenotype concept has been adopted as a framework by some evolutionary biologists and ecologists to study the roles of plant secondary metabolites (PSMs) since Whitham et al. (2003) used helitable variation in tissue tannin concentrations among Populus species and hybrids to develop the concept of community and ecosystem genetics (Antonovics, 1992).