Abstract
The temperature-dependent transmission of mitochondrial DNA (mtDNA) was investigated in heteroplasmic lines of Drosophila melanogaster established by germ-plasm transplantation. Using D. melanogaster, D. simulans and D. mauritiana as germ-plasm donors, five recipient-donor combinations of heteroplasmy, differing from those previously examined (Matsuura et al., 1991), were constructed. For intraspecific reciprocal combinations, donor mtDNA in one combination was retained at 25 degrees C but was almost lost by the tenth generation at 19 degrees C. In the reciprocal, the proportion of the same type of recipient mtDNA decreased more quickly at 19 degrees C than 25 degrees C. Decreasing rates at 19 degrees C in the reciprocals differed from each other. For interspecific combinations, two species were used as germ-plasm donors. Donor mtDNA derived from D. simulans was lost at both temperatures and the rate of decrease was greater at 19 degrees C than 25 degrees C. The proportion of donor mtDNA derived from D. mauritiana increased at a greater rate at 25 degrees C than 19 degrees C when using two different strains of D. melanogaster as recipients. These results suggest that both the nuclear and two types of mitochondrial genomes are involved in the selective transmission of mtDNA.
