Physiological Consequences of Methylation Diets in the Fruit Fly Drosophila melanogaster

Abstract

Dietary intake of nutrients involved in methylation affects the degrees to which organisms can methylate cytosine residues of DNA, which may cause DNA silencing. The relationship of methylating nutrient intake to overall fitness and DNA methylation in the fruit fly Drosophila melanogaster has not been explored. In this study fruit flies were reared on a chemically-defined media with 0, 30, 100, or 300% of dietary folic acid and choline (methyl donors). We predicted that flies reared on lower methyl donor diets would experience more development failures. In support of this prediction, the four treatment groups differed significantly in pupae formed per hatched egg (P=0.037) and in viable adults formed per pupae (P=0.05). The 30% treatment group averaged the fewest pupa per egg at 44.1%, compared to 71.8, 55.3, and 55.0% for 0, 100, and 300% groups respectively. However, this group had the greatest percent of adults to form from pupa (96.3 compared to 93.2, 86.2, and 86.8% for 0, 100, and 300% respectively). Thus, while fewer of the 30% larvae were able to pupate, more of those that did pupate became viable adults. While greater fractions of the 0% flies were able to pupate and emerge than the 30% group, the 0% group produced the least mean number of offspring (33 compared to 40, 44, and 39 for 30, 100, and 300% respectively). These data suggests that low dietary methyl donors have a negative impact on fitness and reproductive output in the fruit fly. In addition, these effects do not appear as severe as those seen in mammals. Further studies will explore the link between dietary methyl donors and DNA methylation state. Funding for this project was provided by support from MGE@MSA to SAB and NSF Grant LMS0065 to JFH.