Evolutionary transitions in plant reproductive systems

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Immobility, hermaphroditism, modularity, and reliance on pollen vectors shape the evolution of plant reproductive diversity. Understanding the evolutionary processes governing transitions in reproductive systems is recognized as a central problem in evolutionary biology since Darwin's pioneering work on plants. Studies of plant reproduction provide some of the best examples of the evolution of adaptation by natural selection and of the maintenance of polymorphisms by frequency-dependent selection. Today, the study of plant reproduction is critical for advances in a range of applied fields, including plant breeding and biotechnology, conservation and invasion biology, and assessment of the environmental consequences of genetically modified organisms. The goal of my research is to understand how and why transitions occur between plant reproductive systems. To achieve this my laboratory exploits the striking intra and interspecific variation in pollination and mating systems evident in many flowering plant groups. We employ diverse approaches to test theoretical models concerned with the evolution and functional significance of sexual diversity. These include phylogeny reconstruction, comparative biology, functional morphology, molecular ecology and the tools of ecological and evolutionary genetics. This grant addresses four general questions concerned with evolutionary transitions. Two are logical extensions of previously funded NSERC projects whereas the other two represent new directions. The research aims at answering the following questions: 1) What selective forces account for variation in gender strategies and sex-ratio variation in dioecious plants? 2) What are the genomic consequences and genetic architecture responsible for the evolution of selfing from outcrossing? 3) In heterostylous plants, what mechanisms cause biased morph ratios and transitions between sexual systems? 4) Why does wind pollination evolve from animal pollination? This research should provide new insights into the evolutionary processes responsible for the spectacular sexual diversity of flowering plants. It will also result in the training of high caliber graduate students & PDFs with broad expertise in ecology & evolutionary biology.