synergistic epistasis
Whitlock MC & Bourguet D 2000 Factors affecting the genetic load in Drosophila: synergistic epistasis and correlations among fitness components. Evolution 54:1654-1660.
- for years, the only direct information came from Mukai's (1969) study of the epistatic effects of mutations accumulated in lines of Drosophila melanogaster
- Mukai's study found evidence for synergistic epistasis based on a quadratic relationship between log viability and the presumed number of accumulated mutations
- based on a number of assumptions, including that the period of mutation accumulation was proportional to the number of mutations accumulated, and the significance to the result rests on two datapoints that are not independent
- a great deal of theoretical literature rests on the single datapoint of Mukai (1969), which gives some evidence for the presence of synergistic epistasis in novel mutations in Drosophila
- this new experiment reinforces the possibility that this synergism is more general
- there is no evidence for directional epistasis in the interactions of loci determining relative male mating success
