Non-Mendelian Inheritance of "Heat-Sensitivity" in Drosophila Melanogaster

Non-Mendelian inheritance was revealed for the "heat-sensitivity" character of the poikilothermic insect Drosophila melanogaster. Genetic analyses were performed on heat-sensitive (S, S(1)) strains, derived through indirect selection, and on stocks constructed through extensive chromosomal and cytoplasmic substitutions between strains obtained from two replicate cage populations. The populations were kept for about 7 years under different temperatures (14 degrees -25 degrees ) and exhibited different survival. We conclude that the character studied is quantitative, responds to selection pressure and is transmitted through the maternal cytoplasm, while nuclear genes modify its expression.