Cytoplasmic genomes that confer additional longevity in Drosophila melanogaster

The mitochondrial genome has been proposed as a principal site of somatic m utation during ageing. A variation of the error catastrophe model has been proposed, in which ROS damages the mitochondrial genome, which leads to add itional ROS production in a positive feed back cycle. This leads to major D NA damage, bioenergy crisis, and reduced functional capacity in old age and contributes to mortality. Therefore it might be expected that in strains i n which the mitochondrial genomes vary, ROS and bioenergy crisis should cov ary and negatively correlate with longevity. Strains of Drosophila were pro duced which differed in their mitochondria by breeding maternally inherited genomes onto a common nuclear background. The donor strains included two l ong lived and two control strains. Those strains that had the cytoplasmic g enomes from the long-lived strains were also long lived. In these strains R OS production in young flies negatively correlated with longevity supportin g a role for ROS in ageing and/or the death process. Ageing Drosophila show a failure in bioenergy, but the relative strength of this phenotype does n ot segregate with longevity. These data do not support the error catastroph e model, but suggests that the principal outcome of ROS damage that leads t o death is not bioenergy failure, and that bioenergy failure is at least pa rtly due to non-ROS processes.