CAN UNIFORM SELECTION RETARD RANDOM GENETIC DIVERGENCE BETWEEN ISOLATED CONSPECIFIC POPULATIONS?
1984; Oxford University Press; Volume: 38; Issue: 3 Linguagem: Inglês
10.1111/j.1558-5646.1984.tb00315.x
ISSN1558-5646
Autores Tópico(s)Insect-Plant Interactions and Control
ResumoIt has long been understood that different species cannot evolve in exactly identical ways, even in response to identical selection pressures (Simpson, 1950). Each species will respond by changes made possible by its own unique store of genetic variation (Simpson, 1967 p. 165). Thus, parallel evolution among different species has not been construed as an allele-for-allele identity of genetic change, but rather as a similarity in trends of phenotypic change. However, it has not been so widely accepted that even conspecific populations will diverge genetically when subjected to similar selection regimes. It has been argued, for example, that random genetic divergence between conspecific populations is not prevented so much by gene flow as by uniformity of selection pressures acting on isolated populations (Ehrlich and Raven, 1969; Levin, 1979). Implicit in this argument is the assumption that conspecific populations will respond to uniform selection in genetically identical manners. But conspecific populations of many species of animals and plants have diverged under similar selection pressures for a great variety of physiological, biochemical, and morphological characters (Table 1). For instance, different populations of the spider mite Tetranychus urticae have responded to selection for organophosphate (OP) resistance by alternative mechanisms: a New York population has responded by detoxifying the poison, while a European population has altered its neural sensitivity to OP's (Matsumura and Voss, 1964). A model is presented here which suggests that weak, uniform selection im-
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