Analysis of two components of flight using recombinant inbred lines of Drosophila melanogaster

Complex activities require precise coordination of their components for successful action. The genetic basis underlying coordination of traits may range from relatively static pleiotropic associations to more flexible genetic associations that recombine in phenotypes under continuous selective modification by the environment. Successful flight in insects depends on the precise integration of numerous component physiological processes. Here we examine the genetic basis of two of its components, flight duration and rate. To study flight we created recombinant inbred populations from stocks of this laboratory known for their significantly longer duration flights. A heritable basis for these traits was found and determined to be positively correlated between sexes. Correlations of flight length with rate were negative within sexes, suggesting a trade-off, but were significant in males only. Composite interval mapping using the recombinant inbred (RI2) design was used to locate the QTLs for these traits and test for pleiotropy. Four QTLs affecting duration or wing beat rate were found on chromosomes II and III. Tests for pleiotropy showed some effects on traits of QTLs were common to both sexes while others were sex-specific. No QTL was pleiotropic for both traits, suggesting that correlations between flight duration and rate of wing beat are determined by a combination of linkage and environmental factors.