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    Author(s): F. Thomas Ledig; Raymond P. Guries; Barbara A. Bonefeld
    Date: 1983
    Source: Evolution 37(6):1227-1238
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (256 KB)


    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.

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

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