Allozymes and area effects in Cepaea nemoralis on the western Berkshire Downs (original) (raw)

• Original Article
• Published: 01 February 1976

Heredity volume 36, pages 105–121 (1976) Cite this article

• 739 Accesses
• 49 Citations
• Metrics details

Summary

1. 1
   Geographic variation of six loci encoding enzymes (Est-F, Lap-2, Mdh-1, 6pgd, Pgi, and To-2) and of four loci encoding shell characters (C, B, S, and U) in Cepaea nemoralis was examined in the western Berkshire Downs, where there is an extensive area effect for the midband gene, _U_3.
2. 2
   Significant pairwise associations of geographic variation were found for all combinations of the U, S, Est-F, and 6pgd loci. At each of these loci, an allele which is rare outside the midband area reaches moderate to high frequencies within that area. Significant associations of C with U, S, and Est-F, and of S with Mdh-1 also were found. All pairwise associations reflect the area effect.
3. 3
   Multilocus geographic associations were examined by Varimax factor analysis. The midband area effect is well represented by the second Varimax axis, accounting for 20 per cent of the allelic frequency variation over all 10 loci. Variation at the C, U, S, Est-F, and 6pgd loci is correlated with this axis. The first Varimax axis represents structure within the midband area, accounting for 22 per cent of the allelic frequency variation, and with which several loci are correlated.
4. 4
   That several loci are associated with the midband area effect indicates that the area effect reflects substantial genetic differentiation. Whatever the cause of the area effect is, it has acted pervasively.

Similar content being viewed by others

Article PDF

References

• Arnold, R W. 1968. Climatic selection in Cepaea nemoralis (L.) in the Pyrenees. Phil Trans Roy Soc B, 253, 549–593.
  Article Google Scholar
• Arnold, R W. 1971. Cepaea nemoralis on the east Sussex South Downs, and the nature of area effects. Heredity, 26, 277–298.
  Article Google Scholar
• Bantock, C R. 1974. Experimental evidence for non-visual selection in Cepaea nemoralis. Heredity, 33, 409–412.
  Article CAS Google Scholar
• Brewer, G J. 1970. An Introduction to Isozyme Techniques. Academic Press, New York.
  Google Scholar
• Brussard, P F. 1975. Geographic variation in North American colonies of Cepaea nemoralis. Evolution, in press.
• Brussard, P F, and McCragken, G F. 1974. Allozymic variation in a North American colony of Cepaea nemoralis. Heredity, 33, 98–101.
  Article Google Scholar
• Cain, A J. 1971. Colour and banding morphs in subfossil samples of the snail Cepaea. In Ecological Genetics and_Evolution_, pp. 65–92 (ed. R. Creed).Blackwell, Oxford.
  Google Scholar
• Cain, A J, and Currey, J D. 1963a. Area effects in Cepaea. Phil Trans Roy Soc B, 246, 1–83.
  Article Google Scholar
• Cain, A J, and Currey, J D. 1963b. Area effects in Cepaea on the Larkhill Artillery Ranges, Salisbury Plain. Zool J Linn Soc Lond, 45, 1–15.
  Article Google Scholar
• Cain, A J, Sheppard, P M, and King, J M B. 1968. The genetics of some morphs and varieties of Cepaea nemoralis (L.). Phil Trans Roy Soc B, 253, 383–396.
  Article Google Scholar
• Carter, M A. 1968. Area effects and visual selection in Cepaea nemoralis (L.) and Cepaea hortensis. Phil Trans Roy Soc B, 253, 397–446.
  Article Google Scholar
• Clarke, B. 1966. The evolution of morph ratio clines. Am Natur, 100, 389–402.
  Article Google Scholar
• Clarke, B. 1968. Balanced polymorphism and regional differentiation in land snails. In Evolution and Environment, pp. 351–368 (ed. E. T. Drake).Yale University Press, New Haven.
  Google Scholar
• Clarke, B, and Murray, J. 1971. Polymorphism in a Polynesian land snail, Partula suturalis vexillum. In Ecological Genetics and Evolution, pp. 51–64 (ed. R. Creed).Blackwell, Oxford.
  Chapter Google Scholar
• Currey, J D, and Cain, A J. 1968. Climate and selection of banding morphs in Cepaea from the climatic optimum to the present day. Phil Trans Roy Soc B, 253, 483–498.
  Article Google Scholar
• Goodhart, C B. 1963. “Area effects” and non-adaptive variation between populations of Cepaea (Mollusca). Heredity, 18, 459–465.
  Article Google Scholar
• Gould, S J. 1967. Evolutionary patterns in pelycosaurian reptiles: a factor-analytic study. Evolution, 21, 385–401.
  Article Google Scholar
• Jones, J S. 1973. Ecological genetics and natural selection in molluscs. Science, 182, 546–552.
  Article CAS Google Scholar
• Lamotte, M. 1959. Polymorphism of natural populations of Cepaea nemoralis. Cold Spring Harb Symp Quant Biol, 24, 65–84.
  Article CAS Google Scholar
• Levan, G, and Fredga, K. 1972. Isozyme polymorphism in three species of land snails. Hereditas, 71, 245–252.
  Article CAS Google Scholar
• Manwell, C, and Baker, C M A. 1968. Genetic variation of isocitrate, malate, and 6–phosphogluconate dehydrogenases in snails of the genus Cepaea—Introgressive hybridisation, polymorphism, and pollution? Comp Biochem Physiol, 26, 195–209.
  Article CAS Google Scholar
• Markert, C L, and Faulhaber, I. 1965. Lactate dehydrogenase isozyme patterns offish. J Exp Zool, 159, 319–332.
  Article CAS Google Scholar
• Oxford, G S. 1973. The genetics of Cepaea esterases. I. Cepaea nemoralis. Heredity, 30, 127–139.
  Article CAS Google Scholar
• Quenouille, M H. 1972. Rapid Statistical Calculations, 2nd edition. Hafner, New York.
  Google Scholar
• Richardson, A M M. 1974. Differential climatic selection in natural populations of land snail Cepaea nemoralis. Nature, 247, 572–573.
  Article Google Scholar
• Sokal, R R, and Rohlf, F J. 1969. Biometry. W. H. Freeman, San Francisco.
  Google Scholar
• Wright, S. 1965. Factor interaction and linkage in evolution. Proc Roy Soc B, 162, 80–104.
  Google Scholar

Download references

Author information

Author notes

1. Michael S Johnson
   Present address: Department of Ecology and Evolution, State University of New York, Stony Brook, New York, 11794, USA

Authors and Affiliations

1. Department of Genetics, University of Nottingham,
   Michael S Johnson

Rights and permissions

About this article

Cite this article

Johnson, M. Allozymes and area effects in Cepaea nemoralis on the western Berkshire Downs.Heredity 36, 105–121 (1976). https://doi.org/10.1038/hdy.1976.11

Download citation

• Received: 15 September 1975
• Issue date: 01 February 1976
• DOI: https://doi.org/10.1038/hdy.1976.11