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 temperat ure (Matsuura et al., 1991). To investigate the effects of nuclear gen ome on the temperature-dependent transmission, two sets of heteroplasm y were constructed by germ-plasm transplantation, and changes in the r elative proportion of two types of mtDNA were examined at 19 degrees C and 25 degrees C. In heteroplasmy possessing D. melanogaster and D. m auritiana mtDNA, two different nuclear genomes of D. melanogaster were examined after reciprocally substituting the nuclear genomes. In hete roplasmy possessing D. simulans and D. mauritiana mtDNA, nuclear genom es of D. melanogaster, D. simulans and D. mauritiana were used. For ea ch set of mtDNA combination, the modes of temperature-dependent transm ission of mtDNA differed according to the nuclear genome used. From th ese and our previous results (Matsuura et al., 1991; Tsujimoto et al., 1991), it is clear that the temperature-dependent transmission of mtD NA is affected by nuclear genome. This suggests that the nuclear genom e is involved in determining the temperature-dependency of mtDNA trans mission.