Project description:Diet may be modified seasonally or by biogeographic, demographic or cultural shifts. It can differentially influence mitochondrial bioenergetics, retrograde signalling to the nuclear genome, and anterograde signalling to mitochondria. All these interactions have the potential to influence the frequencies of mtDNA types in nature and human health. In a model laboratory system, we fed four diets varying in Protein: Carbohydrate (P:C) ratio (1:2, 1:4, 1:8 and 1:16 P:C) to four Drosophila mitotypes and assayed their frequency in population cages. The nuclear genome was standardised. When fed a high protein 1:2 P:C diet, the frequency of flies harbouring Alstonville mtDNA increased. In contrast, when fed the high carbohydrate 1:16 P:C food the incidence of flies harbouring Dahomey mtDNA increased. This result was repeated when the laboratory diet was replaced by natural fruits having high and low P:C ratios and when the nuclear genome was permuted. Quaternary structural modelling, in vitro assays of electron transport chain protein complexes, and protein gels suggested a V161L mutation in the ND4 subunit of Complex I of Dahomey mtDNA was functionally deleterious and resulted in an increase in larval development time on the 1:2 P:C diet. Conversely, the 1:16 P:C diet resulted in an elegant remodelling of energy metabolism and relative reduction in development time of larvae harbouring Dahomey mtDNA. These data question the use of mtDNA as an assumed neutral maker. We posit that humans with specific mtDNA variations may differentially metabolise carbohydrates, which has implications for a variety of first-world diseases including cardiovascular disease, diabetes, obesity and perhaps Parkinson’s Disease.
