The relation of growth to heterozygosity in pitch pine

Abstract

The connection between fitness and heterozygosity has eluded geneticists for decades. The classic form of the Neo-Darwinian argument hypothesizes that heterozygosity confers genetic homeostasis (Lerner, 1954); i.e., multiple, molecular forms of the same enzyme endow the organism with a broader range of tolerance to environmental variation because different forms may differ in their optima for temperature, pH, and other factors (Johnson, 1976). In maize (Zea mays L.), inbred lines and their hybrids are similar in growth rate when raised under constant u conditions at optimal temperatures, but hybrid superiority becomes progressively more obvious as conditions deviate from the optimum (McWilliam and Griffing, 1965). Apparently, homozygotes in maize can only deal successfully with a narrow range of conditions as compared to heterozygotes.

Citation

Ledig, F. Thomas; Guries, Raymond P.; Bonefeld, Barbara A. 1983. The relation of growth to heterozygosity in pitch pine. Evolution 37(6):1227-1238