Abstract
Directional selection on a quantitative character is predicted to decrease genetic variance and lead to rapid fixation of alleles. However, many traits vary in a dichotomous manner although the underlying genetic determination is polygenic. This paper presents a theoretical examination of the effects of directional selection on a dimorphic trait. Such selection can change the incidence of the selected morph from 50 per cent to 99 per cent within 20 generations. However, after an initial decline heritability is predicted to rise back to its original value. The consequences of a finite number of alleles and loci on this prediction are examined using a simulation model. These simulations show that, unlike the case of directional selection on a continuously distributed trait, there is little loss of genetic variance even when the trait is controlled by only three loci with two alleles per locus.
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Bull, J J, Vogt, R C, and Bulmer, M G. 1982. Heritability of sex ratio in turtles with environmental determination. Evolution, 36, 333–341.
Bulmer, M G. 1976. The effect of selection on genetic variability: a simulation study. Genet Res, 28, 101–117.
Bulmer, M G. 1985. The Mathematical Theory of Quantitative Genetics. Clarendon Press, Oxford, p. 154.
Crespi, B J. 1988. Adaptation, compromise and constraint: the development, morphometries and behavioural basis of a fighter-flier polymorphism in male Hoplothrips karnyi (Insecta: Thysanoptera). Behav Ecol Sociobiol, 23, 93–104.
Danforth, B N. 1991. The morphology and behaviour of dimorphic males in Perdita portalis (Hymenoptera: Andrenidae). Behav Ecol Sociobiol, 29, 235–247.
Dodson, S. 1989. Predator-induced reaction norms. BioScience, 39, 447–452.
Eberhard, W G, and Gutiérrez, E E. 1991. Male dimorphisms in beetles and earwigs and the question of developmental constraints. Evolution, 45, 18–28.
Elmes, G W. 1991. Mating strategy and isolation between the two forms, macrogyna and microgyna, of Myrmica ruginodis (Hym. Formicidae). Ecol Entomol, 16, 411–423.
Falconer, D S. 1989. Introduction, to Quantitative Genetics. Longmans, New York.
Gross, M R, and Charnov, E L. 1980. Alternative male life histories in bluegill sunfish. Proc Natl Acad Sci USA, 77, 6937–6940.
Harris, R N, Semlitsch, R D, Wilbur, H M, and Fauth, J E. 1990. Local variation in the genetic basis of paedomorphosis in the salamander Ambystoma talpoideum. Evolution, 44, 1588–1603.
Hazel, W N, Smock, R, and Johnson, M D. 1990. A polygenic model for the evolution and maintenance of conditional strategies. Proc R Soc Lond B, 242, 181–187.
Janzen, F J. 1992. Heritable variation for sex ratio under environmental sex determination in the common snapping turtle(Chelydraserpentina). Genetics, 131, 155–161.
Lively, C M. 1986. Canalization versus developmental conversion in a spatially variable environment. Am Nature, 128, 561–572.
Mackay, T F C, and Doyle, R W. 1978. An ecological genetic analysis of the settling behaviour of a marine polychaete. 1. Probability of settlement and gregarious behaviour. Heredity, 40, 1–12.
Mani, G S, Clarke, B C, and Shelton, P R. 1990. A model of quantitative traits under frequency-dependent balancing selection. Proc R Soc Lond B, 240, 15–28.
Masaki, S, and Seno, E. 1990. Effect of selection on wing dimorphism in the ground cricket Dianemobius fascipes (Walker). Bol San Veg Plagas (Fuera de serie), 20, 381–393.
Moran, N A. 1992. The evolutionary maintenance of alternative phenotypes. Am Nature, 139, 971–989.
Mori, K, and Nakasuji, F. 1990. Genetic analysis of the wing-form determination of the small brown planthopper, Laodelphax striatellus (Hemiptera: Delphacidae). Res Popul Ecol, 32, 279–287.
Mousseau, T A, and Roff, D A. 1989. Adaptation to seasonality in a cricket: patterns of phenotypic and genotypic variation in body size and diapause expression along a cline in season length. Evolution, 43, 1483–1496.
Mousseau, T A, and Roff, D A. 1989. Geographic variability in the incidence and heritability of wing dimorphism in the striped ground cricket, Allonemobius fasciatus. Heredity, 62, 315–318.
Parker, E D. JR, and Orzack, S H. 1985. Genetic variation for the sex ratio in Nasonia vitripennis. Genetics, 110, 93–105.
Roff, D A. 1986a. The evolution of wing dimorphism in insects. Evolution, 40, 1009–1020.
Roff, D A. 1986b. The genetic basis of wing dimorphism in the sand cricket, Gryllus firmus and its relevance to the evolution of wing dimorphisms in insects. Heredity, 57, 221–231.
Roff, D A. 1990. Selection for changes in the incidence of wing dimorphism in Gryllus firmus. Heredity, 65, 163–168.
Roff, D A. 1992. The Evolution of Life Histories: Theory and Analysis. Chapman and Hall, New York.
Roff, D A, and Fairbairn, D J. 1991. Wing dimorphisms and the evolution of migratory polymorphisms among the insecta. Am Zool, 31, 243–251.
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Roff, D. Evolution of dimorphic traits: effect of directional selection on heritability. Heredity 72, 36–41 (1994). https://doi.org/10.1038/hdy.1994.4
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DOI: https://doi.org/10.1038/hdy.1994.4
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