Effects of the nuclear genome on selective transmission of mitochondrial DNA in Drosophila.

In mitochondrial DNA (mtDNA) heteroplasmy in Drosophila, we previously reported that mtDNA was selectively transmitted depending on temperature (Matsuura et al., 1991). To investigate the effects of nuclear genome on the temperature-dependent transmission, two sets of heteroplasmy were constructed by germ-plasm transplantation, and changes in the relative proportion of two types of mtDNA were examined at 19 degrees C and 25 degrees C. In heteroplasmy possessing D. melanogaster and D. mauritiana mtDNA, two different nuclear genomes of D. melanogaster were examined after reciprocally substituting the nuclear genomes. In heteroplasmy possessing D. simulans and D. mauritiana mtDNA, nuclear genomes of D. melanogaster, D. simulans and D. mauritiana were used. For each set of mtDNA combination, the modes of temperature-dependent transmission of mtDNA differed according to the nuclear genome used. From these and our previous results (Matsuura et al., 1991; Tsujimoto et al., 1991), it is clear that the temperature-dependent transmission of mtDNA is affected by nuclear genome. This suggests that the nuclear genome is involved in determining the temperature-dependency of mtDNA transmission.