Different Genetic Realization of Photonegative Behavior in Drosophila Melanogaster Detected by a Chromosome Substitution Analysis

Abstract

Divergent selection is an important tool to analyze polygenic traits like phototactic behavior of Drosophila. A multitude of papers have been published on different artificial selection modes in this genus (for a review of the literature until 1976 see Grossfield, 1978). The experimental designs used in these studies are quite different. One of them, the Hirsch-Hadler maze (multiple unit classification maze), has become a standard method. In this maze Drosophila flies make a definite number of choices of light vs. dark passages. Wild-type Drosophila melanogaster is on the average slight photone-gative or neutral to light, when tested in the Hirsch-Hadler maze (Markow, 1975). When tested in our Y mazes they are rather photopositive (Kohler, 1977). In any case, there are much individual differences, and artificial selection of highly divergent photonegative and photopositive strains of flies is successful. Nevertheless, the heritability of this trait is low in Drosophila melanogaster.