Genetically controlled environmental variance for sternopleural bristles in Drosophila melanogaster – an experimental test of a heterogeneous variance model

Abstract

The objective of this study was to test the hypothesis that the environmental variance of sternopleural bristle number in Drosophila melanogaster is partly under genetic control. We used data from 20 inbred lines and 10 control lines to test this hypothesis. Two models were used: a standard quantitative genetics model based on the infinitesimal model, and an extension of this model. In the extended model it is assumed that each individual has its own environmental variance and that this heterogeneity of variance has a genetic component. The heterogeneous variance model was favoured by the data, indicating that the environmental variance is partly under genetic control. If this heterogeneous variance model also applies to livestock, it would be possible to select for animals with a higher uniformity of products across environmental regimes. Also for evolutionary biology the results are of interest as genes affecting the environmental variance may be important for adaptation to changing environmental conditions.

Keywords:

• Drift
• environmental variance
• genetic variance
• inbreeding
• model comparisons

Acknowledgements

We are grateful to Tatyana A. Rakitskaya and Doth Andersen for excellent technical assistance, to Oleg Bubliy for his help in planning the logistics of the experiments, to Kamilla Pedersen for managing the Drosophila lines, and to the Danish Natural Science Research council (centre grant and frame grant) and the Danish Agricultural and Veterinary Research Council for financial support.