Longevity, Habitat, and Release of Genetic Variability in the Higher Plants
Recent studies of population genetics, as summarized in the Cold Spring Harbor Symposium for 1955 (Lerner, 1955; Dobzhansky, 1955), have shown us that natural populations of cross-fertilizing organisms normally possess an enormous store of hidden variability, in the form of recessive genes for which their individuals are heterozygous. In the past, this variability has been regarded as a load of deleterious genes which the population must bear as insurance for the future. Now, however, we have a large enough number of examples pointing toward the superior adaptiveness of heterozygotes per se (Lerner, 1954, 1955; Dobzhansky, 1955), so that we can regard some of this hidden variability as of positive value to the population.