Efficiency of feedback selection for recombination in Drosophila
1991
Population genetic theory has developed a number of models for the evolution of recombination systems, directed by natural selection for adaptive properties. We have subjected large captive Drosophila populations to selection for resistance to diurnal temperature variations, with increasing amplitude in each generation, and we report the effects of such selection on the rec system. It was found that selection for adaptability to unfavorable conditions led to a significant increase in the crossing-over frequency at different genome segments over several tens of generations, especially at b-cn and ru-h, in chromosomes 2 and 3 respectively; selection also led to changes in exchange interference in adjacent and non-adjacent segments. These results provide the first experimental support for Fisher's hypothesis suggesting increased gene linkage in optimal, constant conditions. Adaptive differences in resistance to diurnal temperature variations were found between experimental and control populations.
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