Selection for central excitation in Drosophila melanogaster.

In two populations of Drosophila melanogaster, bidirectional selection and single-pair matings for high and low expression of central excitatory state (CES) succeeded in producing from one a high, but not a low, CES line, and from the other a low, but not a high, CES line. Compared with results from the selection studies of the blow fly, Phormia regina, in which one major gene correlate of CES has been found, the results from this study suggest that in D. melanogaster there are several gene correlates of CES, opposite alleles of some of which have become fixed in the divergent lines.