A Hypothesis of Developmental Selection Exemplified by Lethal and Semi-Lethal Mutants of Arabidopsis

Abstract

A hypothesis of developmental selection is presented in which the internal factors of selection, barriers imposed by ontogenetic development, are considered in relation to the degree of survival of newly arisen deleterious mutations. This hypothesis states that the survival of such mutant genes to the stage of germination depends on the diffusibility of the metabolite required by the mutants and the ontogenetic stage at which it is required. As a corollary of the hypothesis, those lethal mutants of flowering plants that appear after germination should, with certain predictable exceptions, have requirements for low molecular weight substances which may be supplied from external sources.