Supplementary Figure 3: D. mauritiana mtDNA rapidly outcompeted three D. melanogaster mitochondrial genotypes at 25 °C in the D. melanogaster nuclear background.

(a) The starting abundance for endogenous wild-type D. melanogaster mtDNA was high, but the abundance decreased to a low percent after four generations in two heteroplasmic lineages. PCR using primers to common sequences amplified a region of mtDNA (mt11517–12529) from both genomes. XhoI cutting was used to selectively cleave the product derived from D. mauritiana. Separation on agarose gels showed one large band representing the D. melanogaster genome and two smaller bands representing the D. mauritiana genome. The changing ratio of the top two bands illustrates the declining relative abundance of the D. melanogaster genome and the increase in the D. mauritiana genome. (b) qPCR performed as described in the Online Methods showed that the level of D. mauritiana mtDNA increased quickly when the recipients were flies homoplasmic for mt:ND2^del1 + mt:CoI^T300I or mt:ND2^del1. After a few generations, D. melanogaster flies were left with only D. mauritiana mtDNA.