Simultaneous expression of Bsub\BglII^{Scer\UAS.P\T.T:Mito-kdn} and Xvas\XhoI^{Scer\UAS.P\T.T:Mito-kdn,T:Hsap\MYC} restriction enzymes under the control of Scer\GAL4^nos.PU in flies that are homoplasmic for mt:CoI^R301Q (which lacks the XhoI restriction site) lead to sterility in females. Upon selection, about 1% percent of the females become weakly fertile producing a small number of escaper progeny that harbor a variety of mutations that inactivate the BglII restriction site. In contrast, when the flies are heteroplasmic for mt:CoI^R301Q and mt:ND2^del1 (in a 50:50 ratio), the Scer\GAL4^nos.PU-driven expression of both Bsub\BglII^{Scer\UAS.P\T.T:Mito-kdn} and Xvas\XhoI^{Scer\UAS.P\T.T:Mito-kdn,T:Hsap\MYC} does not lead to sterility - more than 90% of the females are fertile and most display fecundity comparable to that of wild-type females. Scer\GAL4^ey.PU-driven expression of the two restriction enzymes at 29[o]C results in pupal lethality (headless pupae) in a vast majority of flies and the few escapers are eyeless or have a small eye phenotype, in heteroplasmic flies a larger proportion of individuals (~10%) manage to eclose and most of the survivors have well developed eyes.

Heteroplasmic flies containing in addition to the wild-type mitochondrial (mt) genome also both mt:CoI^R301Q and mt:ND2^del1 kept at 29[o]C (to select against the mutant genomes) and also expressing Bsub\BglII^{Scer\UAS.P\T.T:Mito-kdn} under the control of Scer\GAL4^nos.PU (to select against the wild-type mt genome) can produce viable female offspring: about 15% of the females are both viable and fertile and produce progeny that show the repaired, wild-type sequence at the CoI gene while also harboring the mt:ND2 [del1] mutation.

The eye ablation phenotype caused by expression of Xvas\XhoI^{Scer\UAS.P\T.T:Mito-kdn,T:Hsap\MYC} under the control of Scer\GAL4^ey.PB is completely suppressed if the animals also carry mt:CoI^R301Q.