New Forests

, Volume 6, Issue 1–4, pp 179–196

Evidence for the adaptive significance of allozymes in forest trees

  • Robin M. Bush
  • Peter E. Smouse
Review paper Biosystematics and adaptive significance of biochemical markers


Positive correlations between allozyme heterozygosity and fitness measures, primarily growth and fecundity, have been reported for a number of forest tree species. Because the amount of variation in growth explained by allozyme genotype is usually on the order of only a few percent, there has been little effort made towards using electrophoretic screening of allozymes as a tool in early selection on seedlings in production nurseries. We review the progress made in studies of heterozygosity in forest trees, focusing on how recent studies have utilized careful experimental design to allow testing of hypotheses as to the causative nature of the heterozygosity-fitness phenomena. We discuss evidence suggesting a deleterious nature for rare allozyme alleles, and present a case of apparent balancing selection across life history stages acting to maintain rare alleles in Pinus taeda. We also review the apparently common trend in natural stands toward increasing heterozygosity over time, and suggest how gains might be made through artificial selection based on allozyme survey data.

Key words

adaptive distance heterosis inbreeding depression overdominance rare alleles 


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Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Robin M. Bush
    • 1
  • Peter E. Smouse
    • 2
  1. 1.Department of Ecology and Evolutionary BiologyUniversity of CaliforniaIrvineUSA
  2. 2.Center for Theoretical and Applied GeneticsCook College, Rutgers University New BrunswickUSA

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