Change in the maternal effect in Drosophila hybrids at low temperatures.

Interspecies Drosophila hybrids of the virilis group were used to study the maternal effect (expression of the recessive glossy mutation when females of D. virilis strains carrying this mutation are crossed with D. littoralis males of the wild type) at low temperatures. The maternal effect was found to be intensified by a factor of four at 17 degrees and there was also an increase in the incidence of haplo-6 individuals (95%, as against 26% at 25 degrees), apparently as a result of the increased frequency of elimination of the 6th D. littoralis chromosome during cleavage division I.