Molecular Genetic Analysis Of A Seasonal Character In D Melanogaster Natural Populations PDF Download

A major challenge for modern Biology involves the elucidation of the genetic and molecular mechanisms that underlie natural variation in behavioural phenotypes. In the fruit fly, Drosophila melanogaster, many genes that influence behaviours have been identified, primarily as a result of their mutant effects. However, the contributions of variation in these genes to naturally maintained behavioural variation is often unknown. The identification of genetic variation effecting naturally maintained behavioural variation will provide insight for therapeutic interventions. By resolving and quantifying the plasticity or flexibility present and maintained in the molecular cascades that regulate behavioural responses in natural populations, researchers will identify therapeutic limits within which it may be possible to manipulate the systems while potentially minimizing undesirable side effects. Toward enhancing the understanding of the genetic bases of natural behavioural variation, this thesis presents research on three different phenotypes, each of which have been previously described to different degrees. The first study involves an investigation meant to further resolve the molecular mechanism by which allelic variation in the for gene effects differences in foraging behaviours. The second study presents efforts to identify the genetic basis for variation in pupation position, a well-studied behaviour with known fitness consequences, and presents an initial description of associated variation in wandering behaviours. The third study investigates pupation behaviour from a more physiological perspective. In this study it was observed that larvae selected for high NaCl tolerance, which may have altered osmoregulatory abilities, pupate significantly farther from their growth media than do wild-type larvae. As a result, an effort was made to map the genetic factors effecting natural variation in NaCl tolerance. Taken as a whole, this work has the potential for extending the mechanistic understanding of complex interactions between genetic and environmental effects and the resultant behavioural responses.