Genetica

, Volume 48, Issue 2, pp 81–87

Investigation on early divergence between populations of Drosophila melanogaster kept at different temperatures

  • S. Cavicchi
  • G. Giorgi
  • M. Mochi
Article

An experiment was performed on Drosophila melanogaster populations kept at two temperatures (25°C and 28°C) with the aim of providing further evidence that:
  1. 1

    phenotypic differentiation between the two populations is already detectable in earlier generations of selection;

     
  2. 2

    the divergence is more related to a changed body shape than to body size;

     
  3. 3

    this divergence is correlated with fitness and, therefore, natural selection may operate on these differences.

     
The results obtained by univariate and multivariate statistical analysis imply that:
  1. (i)

    progress in the phenotypic divergence is observed from the first to the sixth generation as based on the discrimination by a linear function of nine metric traits of the wing, while, as expected, divergence is not detected on mean values and variance estimates;

     
  2. (ii)

    differential reproductive fitness is associated with these differences and not with single traits.

     

It is suggested that the kind of variation observed is the outcome of a rearrangement of the developmental pattern of the wing in the population kept at different temperatures and that the reproductive fitness values are more dependent on the developmental pattern than on the genetic basis of a given character.

The results are discussed in terms of population dynamics.

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References

  1. Anderson, W.W. (1966). Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura. 3. Divergence in body size. Genet. Res. 7: 255–266.Google Scholar
  2. Anderson, W.W. (1973). Genetic divergence in body size among experimental populations of Drosophila pseudoobscura kept at different temperatures. Evolution 27: 278–284.Google Scholar
  3. Cannon, G.B. (1963). The effects of natural selection on linkage disequilibrium and relative fitness in experimental populations of Drosophila melanogaster. Genetics 48: 1201–1216.Google Scholar
  4. Cavicchi, S. (1970) Conseguenze della selezione in Drosophila. Relazione tra carattere e fitness nella selezione per lunghezza delle ali. Atti Ass. Genet. Ital. 15: 210–219.Google Scholar
  5. Cavicchi, S. & M. Mochi (1977). Phenotypic differentiation between population of Drosophila melanogaster in contrasting environments. Monit. Zool. Ital. (in press)Google Scholar
  6. Davies, R.G. (1971). Computer programming in quantitative biology. Academic Press, London and New York.Google Scholar
  7. Dobzhansky, Th. (1951). Mendelian populations and their evolution. In: L.C. Dunn, Ed., Genetics in the 20th Century. New York, McMillan Co.Google Scholar
  8. Ehrman, L. (1964). Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura. I. Rudiments of sexual isolation. Genet. Res. 5: 150–157.Google Scholar
  9. Ehrman, L. (1969). Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura. 5. A further study of rudiments of sexual isolation. Am. Midl. Nat. 82: 272–276.Google Scholar
  10. Ewing, A.W. 1964. The influence of wing area on the courtship behaviour of D. melanogaster. Anim. Behav. 12: 316–320.Google Scholar
  11. Kitagawa, O. (1967). Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura. 4. Relative viability. Genet. Res. 10: 303–312.Google Scholar
  12. Lerner, I.M. (1954). Genetic homeostasis. Oliver and Boyd. Edinburgh.Google Scholar
  13. Lerner, I.M. (1958). The genetic basis of selection. J. Wiley, New York.Google Scholar
  14. Misra, R.K. & E.C.R., Reeve (1964). Clines in body dimensions in populations of Drosophila pseudoobscura. Genet. Res. 5: 240–256.Google Scholar
  15. Mochi, M., G., Giorgi & D.L., Palenzona (1973). Fitness and genetic heterogeneity in laboratory populations with overlapping generations. Monit. Zool. Ital. 9: 1–9.Google Scholar
  16. Mourad, A. (1965). Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura. 2. Longevity. Genet. Res. 6: 139–146.Google Scholar
  17. Palenzona, D.L., G., Rocchetta & A., Jacuzzi (1972). The relationships between fitness and response to selection in Drosophila melanogaster. Theoret. appl. Genet. 42: 65–68.Google Scholar
  18. Parsons, P.A. 1977. Genes, behaviour and evolutionary processes: the genus Drosophila. Adv. Genet. 19: 1–27.Google Scholar
  19. Prevosti, A. (1955). Geographical variability in quantitative traits in populations of Drosophila subobscura. Cold Spring Harbor Symp. Quant. Biol. 20: 294–299.Google Scholar
  20. Seal, H. (1964). Multivariate statistical analysis for biologists. Methuen, London.Google Scholar
  21. Snedecor, G.W. & W.G., Cochran (1967). Statistical Methods. The Iowa State Univ. Press, Ames, Iowa, U.S.A.Google Scholar
  22. Vanelli, M., R., Alicchio & D.L., Palenzona (1972). Investigation of a coadapted gene pool. Monit. Zool. Ital. 6: 239–250.Google Scholar

Copyright information

© Dr. W. Junk b.v 1978

Authors and Affiliations

  • S. Cavicchi
    • 1
  • G. Giorgi
    • 1
  • M. Mochi
    • 1
  1. 1.Istituto di GeneticaUniversità di BolognaItaly

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