Abstract
AbstractJuveniles are often first to suffer from nutrient shortage, and juvenile undernutrition is likely an important force of natural selection shaping animal physiology, with consequences potentially extending into adulthood. We combined RNAseq, targeted metabolomics and genomics to study the consequences of experimental evolution under juvenile undernutrition for metabolism of reproductively active adult females of Drosophila melanogaster. Compared to six Control populations maintained on standard diet, six Selected populations evolved for over 230 generations on a nutrient-poor larval diet showed major changes in adult gene expression and metabolite abundance. In particular, Selected flies were relatively deficient in essential amino acids and purine nucleotides, but showed overabundance of several non-essential amino-acids involved in purine synthesis and overexpression of multiple enzymes catalyzing this pathway. Selected flies also accumulated medium-chain acylcarnitines suggestive of congestion in beta-oxidation, possibly linked to deficiency of electron transporters. Some aspects of the metabolic profile of Selected flies resembled that of flies subject to starvation. Furthermore, differences between Selected and Control populations in adult gene expression were in general positively correlated with differences in larval expression, consistent with pleiotropy in gene regulation between the life stages. Finally, Selected flies were less fit in terms of fecundity than Controls even when both were raised under the conditions under which the Selected populations evolved. These results suggest that evolutionary adaptation to juvenile undernutrition has large pleiotropic consequences for adult metabolism, and that they are costly rather than adaptive for adult fitness.
Publisher
Cold Spring Harbor Laboratory