Chromosomal and Cytoplasmic Analysis of Heat Shock Resistance in Natural Populations of Drosophila Melanogaster

Abstract

We evaluated genetic differences between two populations of Drosophila melanogaster that differed in thermal tolerance. Adults of one tropical population (Mali) survived heat shock (39.5°C for 30 min.) at 84%. By contrast, those from a strain collected in Denmark survived at a rate of only 53%. The greatest effect on variation was differences in cytoplasms, but variation in chromosomes 2 and 1 also played a role on tolerance. Heat shock proteins, however, reside on chromosome 3 and, therefore, variation at these sites is low or differences had little effect on results obtained from the methods employed.