MONTOOTH, K.L.*; CLARK, A.G.; MARDEN, J.H.: Physiological genetics of flight performance in Drosophila melanogaster.

Given the high demand that insect flight places on glycolytic metabolism, insect flight performance should be particularly sensitive to the functional effects of allelic and regulatory variation in energy metabolism. However, the contribution of variation in energy metabolism to variation in flight performance has yet to be quantified in a systematic manner, and the genetic basis for this variation is not well characterized. Using a computerized tracking system, we quantified variation in components of free-flight performance among genetically characterized lines of D. melanogaster. From frame-to-frame changes in three-dimensional location we calculated path velocity, acceleration and angular trajectory for individual flights. Differences among lines were found to be far greater than the variability among replicate flights of flies from the same line. Measures of genetic variation in components of free-flight performance among 98 recombinant-inbred lines of D. melanogaster were used to construct a map of Quantitative Trait Loci (QTL). The QTL map revealed regions of the genome that were significantly associated with variation in flight performance. The relationship between variation in flight performance and variation in metabolic rate, metabolic enzyme activity, and glycogen and triacylglycerol concentration was investigated using multiple regression models. The extent to which regions of the genome exhibited pleiotropic effects on multiple metabolic traits will also be discussed. This quantitative genetic approach gives us insight into what might be the genetic response to selection on whole organism physiological performance. Supported by NSF and HHMI.