Genotype to phenotype: Diet-by-mitochondrial DNA haplotype interactions drive metabolic flexibility and organismal fitness
Population cage studies, numbers of flies eclosing in 3 d, and egg counts show that larvae harbouring Alstonville mtDNA had an advantage on the 1:2 P:C diet while those with Dahomey mtDNA had the advantage when fed 1:16 P:C food. (A) Initial studies competed D. melanogaster w1118 flies harbouring four mitotypes fed four Protein: Carbohydrate (P:C) diets (n = 3 cages/diet). The mitotypes were Alstonville, Dahomey, Japan and w1118. The P:C ratios were 1:2 (top left), 1:4 (top right), 1:8 (bottom left) and 1:16 (bottom right). The mitotype of 4,608 flies was determined by amplifying ~900bp of mtDNA and then Sanger sequencing. After 12 generations, Alstonville had the highest frequency on the 1:2 P:C diet while Dahomey was highest on 1:16 P:C food. Flies with Japan or w1118 mtDNA declined in frequency in all diets. Symbols show mean± s.e.m. (B) Eclosion percentage in a 3 d window for four mitotypes fed the 1:2 P:C or 1:16 P:C diet (n = 6 bottles/mitotype/diet) with each bottle seeded with 214.5± 14.2 eggs/bottle. t-tests compared Alstonville with Dahomey (see text). (C) Flies from each mitotype were assayed for fecundity on the 1:2 P:C and 1:16 P:C diets by egg count over 3 d, with an average of 32 flies/mitotype/diet. t-tests compared Alstonville + Dahomey with Japan + w1118 (see text). Bars show mean± s.e.m. * p< 0.05, ** p< 0.01, *** p< 0.001.