The availability of molecular and morphological markers in a parthenogenetically reproducing strain of Drosophila mercatorum allowed us to design an experiment in which we could obtain a sample of completely homozygous recombinant females from two different parental homozygous strains. The phenotypic values of body-size-related measures and bristle numbers (sternopleural and abdominal) were measured in females sampled from the parental, F1 and F2 generations. The DNA extracted from the F2 flies was scored for five Mendelian segregating loci through double stringency PCR. In addition, the flies were scored for three morphological recessive loci. We estimated all single-locus and all two-loci associations between the marker loci with the principal components of the morphological data, which allowed us also to estimate the epistatic parameters. The results suggest that the underlying genetic architecture of the morphological phenotypes cannot be regarded as a result of additivity only, but instead, involves many different kinds of interactions that are distributed around an additive mean.
Bibliographical noteFunding Information:
The authors thank Susan Pletcher because of her expertise on dealing with such delicate flies, and Flora M.C. Fernandes-Matioli for helpful comments on the manuscript. This work was supported by NIH Grant R01 GM31571 to A.R.T. and Grant 93/3328-1 from FAPESP to S.R.M.
- Body size
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