Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Biology

Supervisor

Amanda Moehring

Abstract

Speciation can occur when accumulated differences in mating behavior force diverging species to remain reproductively isolated from one another. A key determinant of behavioural isolation is the evolution of female mating preferences that prevent interspecific males from mating. However, no individual genes involved in species-specific preferences of females have yet been identified. Using various genetic mapping techniques available for studying strains and species of Drosophila, I identify candidate genes involved in D. simulans female discrimination against D. melanogaster males. One candidate gene in particular, Katanin-60, was selected for further characterization. Katanin-60 is a gene encoding a microtubule severing protein that has been previously implicated in Drosophila behaviour. Transgenic rescue of Katanin-60 expression using the GAL4/UAS system revealed the potential involvement of specific neural lobes of the Mushroom bodies in interspecific discrimination. Further characterization of the behaviour through modifying male mating signals showed that the type-aversive cue females are discriminating against is found in male wing song. However, this was not true of all strains and species tested, indicating that many means of mate assessment have diversified within the genus. One other species, D. sechellia, was additionally mapped for their females’ discrimination against D. simulans males. Quantitative trait locus mapping identified two loci for interspecific preference that were then compared to other maps of interspecific divergence between the two species.

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