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Warfarin resistance: a balanced polymorphism in the Norway rat

Published online by Cambridge University Press:  14 April 2009

J. H. Greaves ,
R. Redfern ,
P. B. Ayres  and
J. E. Gill
J. H. Greaves
Affiliation:
Pest Infestation Control Laboratory, Ministry of Agriculture, Fisheries and Food, Hook Rise South, Tolworth, Surrey
R. Redfern
Affiliation:
Pest Infestation Control Laboratory, Ministry of Agriculture, Fisheries and Food, Hook Rise South, Tolworth, Surrey
P. B. Ayres
Affiliation:
Pest Infestation Control Laboratory, Ministry of Agriculture, Fisheries and Food, Hook Rise South, Tolworth, Surrey
J. E. Gill
Affiliation:
Pest Infestation Control Laboratory, Ministry of Agriculture, Fisheries and Food, Hook Rise South, Tolworth, Surrey
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The frequency of monogenic resistance to anticoagulant rodenticides in Rattus norvegicus in an area straddling the England–Wales border was monitored from 1967 until 1975. Rats were trapped on farms and tested in the laboratory by administering a dose of warfarin lethal to susceptibles. The mean incidence of resistance was 44% and did not change significantly, despite the extensive use of anticoagulants by farmers during the 9-year period. In 1975 more refined techniques showed that the frequencies of susceptible (SS) and resistant (RR) homozygotes were significantly below the Hardy–Weinberg expectations and simple estimates of the relative fitness ratios for the RR, RS and SS phenotypes were 0·37, 1·0 and 0·68 respectively. In two relatively isolated valleys, where selection with anticoagulants was minimal, the frequency of resistance decreased significantly from 57% to 39% during 1973–5. The results are consistent with the hypothesis that a balanced polymorphism is being maintained. Selection against susceptible homozygotes by the use of anticoagulant rodenticides, and against the resistant homozygote due to its high susceptibility to a primary deficiency of vitamin K gives the heterozygotes a selective advantage. A number of ecological factors that influence the incidence of the resistance are discussed briefly.

Type
Research Article
Information
Genetics Research , Volume 30 , Issue 3 , December 1977 , pp. 257 - 263
Copyright
Copyright © Cambridge University Press 1977

References

REFERENCES

Bell, R. G. & Caldwell, P. T. (1973). Mechanism of warfarin resistance. Warfarin and the metabolism of vitamin K1. Biochemistry 12, 1759–1762.CrossRefGoogle Scholar
Bell, R. G., Sadowksi, J. A. & Matschiner, J. T. (1972). Mechanism of action of warfarin. Warfarin and metabolism of vitamin K1. Biochemistry 11, 1959–1961.CrossRefGoogle Scholar
Bishop, J. A. & Hartley, D. J. (1976). The size and age structure of rural populations of Rattus norvegicus containing individuals resistant to the anticoagulant poison warfarin. Journal of Animal Ecology 45, 623–646.CrossRefGoogle Scholar
Calhoun, J. B. (1962). The Ecology and Sociology of the Norway Rat. U.S. Public Health Service Publication no. 1008. Washington, D.C.Google Scholar
Drummond, D. (1966). Rats resistant to warfarin. New Scientist 30, 771–772.Google Scholar
Ford, E. B. (1971). Ecological Genetics, 3rd ed., p. 350. London: Chapman and Hall.Google Scholar
Greaves, J. H. & Ayres, P. (1967). Heritable resistance to warfarin in the rat. Nature 215, 877–878.CrossRefGoogle Scholar
Greaves, J. H. & Ayres, P. (1969 a). Linkages between genes for coat colour and resistance to warfarin in Rattus norvegicus. Nature 224, 284–285.CrossRefGoogle ScholarPubMed
Greaves, J. H. & Ayres, P. (1969 b). Some rodenticidal properties of coumatetralyl. Journal of Hygiene 67, 311–315.CrossRefGoogle ScholarPubMed
Greaves, J. H. & Ayres, P. (1973). Warfarin resistance and vitamin K requirement in the rat. Laboratory Animals 7, 141–148.CrossRefGoogle ScholarPubMed
Hadler, M. R., Redfern, R. & Rowe, F. P. (1975). Laboratory evaluation of difenacoum as a rodenticide. Journal of Hygiene 74, 441–448.CrossRefGoogle ScholarPubMed
Hadler, M. R. & Shadbolt, R. S. (1975). Novel 4-hydroxycoumarin anticoagulants active against resistant rats. Nature 253, 272–277.CrossRefGoogle ScholarPubMed
Hermodson, M. A., Suttie, J. W. & Link, K. P. (1969). Warfarin metabolism and vitamin K requirement in the warfarin resistant rat. American Journal of Physiology 217, 1316–1319.CrossRefGoogle ScholarPubMed
Redfern, R., Gill, J. E. & Hadler, M. R. (1976). Laboratory evaluation of WBA 8119 as a rodenticide for use against warfarin-resistant and non-resistant rats and mice. Journal of Hygiene 77, 419–426.CrossRefGoogle ScholarPubMed