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Title: Biometrical and population genetic studies of the dimethoate resistance of Danish houseflies
Author: Gibson, J. P.
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 1980
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The resistance of houseflies to a particular insecticide is often complex, involving several genes. In this light, the work detailed in this thesis set out to examine (i)o alternatives to standard chromosome isolation procedures, for genetic analysis of multi-factorial resistances, and (ii) available data on the evolution of a multifactorial resistance (dimethoate) in the field, in order to see whether they would afford inferences of the population genetic processes involved. Preliminary laboratory studies demonstrated a partial dependence of LOG LDSO on LOG weight. Therefore, in all experiments the covariance of LOG LDSO and LOG weight was taken into account and used for a partial control of error. A Cavalli design (comparison of two inbred parental strains, their FI, F2, and first backcross generations) was employed in a biometrical genetic analysis of dimethoate resistance, and found to yield acceptable results when both parents were inbred, but to be of little use when one parent was not inbred. The main use of this design would be where mutant markers suitable for chromosome isolation are not available. A heterozygous chromosome assay proved straight forward and, given its speed and accuracy, was thought to have several advantages over standard chromosome isolation procedures. Analysis of data on the evolution of dimethoate resistance in farm populations of houseoflies in Denmark, faced severe problems caused by migration of flies between farms, which was hitherto thought to be of little importance. Apart from this difficulty, modelling of the evolution of dime tho ate resistance was thought':oto be inappropriate as estimates of many essential parameters were lacking. A trial of the Lincoln Index method for estimating the sizes of farm populations of houseflies was largely unsuccessful due to the failure of several assumptions of the method. A population cage for the continuous rearing of houseflies was developed Q.nd its possible rele in future population genetic studies of insecticide resistance is discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Zoology Zoology Ecology