Genetic analysis of temperature-dependent transmission of mitochondrial DNA in Drosophila

In artificially induced mitochondrial DNA (mtDNA) heteroplasmy in Drosophila, the effects of chromosome substitution on temperature-dependent selection in mtDNA transmission were investigated. Using two strains of D. melanogaster, bw;e11 and y;bw;st, which showed a different temperature dependency in mtDNA transmission, chromosomes were substituted reciprocally, and mtDNA of D. mauritiana was introduced into each newly constructed strain. For each heteroplasmy, the transmission of mtDNA was examined at 25 degrees C and 19 degrees C. When either the second or the third chromosome of the y;bw;st strain was substituted with that of the bw;e11 strain, the temperature-dependent selection in mtDNA transmission was altered. The selection was not changed when either the second or the third chromosome of the bw;e11 strain was substituted with that of the y;bw;st strain, or even when both the second and the third chromosomes of the bw;e11 strain were substituted with those of the y;bw;st strain. These results suggest that the temperature-dependent selection in mtDNA transmission is co-operatively regulated by gene products that are encoded by the X, second and third chromosomes.