Even before the influence of Charles Darwin (at least from the time of Aristotle, 324-388 B.C.), questions pertaining to the hows and whys of sex and reproduction have been recognized among the central unanswered questions in biology. Framed in modern terms, this is because the likelihood of genetic exchange among individuals, which is primarily determined by how organisms reproduce, is one of the most important known influences on evolutionary change—structuring both levels of genetic variation and rates of evolution within populations. Indeed, factors influencing how, when, and with whom organisms reproduce are at the heart of the maintenance of genetic variation, rates of adaptation, and the evolution of sex, sexes, sex-ratio, sexual conflict and competition, and life history strategies.
My research focuses on identifying and understanding:
- the effects of genetic exchange on genetic diversity, fitness, and adaptive evolution
- intraspecific and intergenerational variation in sex-ratio and rates of genetic exchange, and the genes underlying this variation
- forces shaping the evolution and maintenance of mixed modes of reproduction
- the evolution of sex specific phenotypes and intersexual conflict
I use organisms from two kingdoms of life in my research, capitalizing on my expertise in fungi and in the model nematode C. elegans. I have also expanded my research efforts into the vertebrate model Danio rerio (zebrafish) in a collaborative capacity. My expertise in these different systems affords me the flexibility to answer fundamental questions in biology using powerful natural and model systems.
Tetracladium marchalianum: An ecologically important, microscopic, freshwater fungus. I am currently sequencing the genome of this fungus. Using clues from the genome I will determine whether this species is capable of reproducing sexually.
Neurospora spp: Conidiating species in the genus Neurospora produce vast amounts of orange, asexual, spores on scorched vegetation. These fungi have sequenced genomes and are powerful genetic model organisms. I am currently exploring the performance effects of degenerating mating type chromosomes and interspecies introgression in N. tetrasperma. I am also experimentally manipulating reproduction in N. crassa to look for sex-role related tradeoffs.
Caenorhabditis elegans: This soil-dwelling nematode has long been recognized as a powerful genetic and developmental model, but it is now proving to be a powerful evolutionary model as well. I am using this worm to study intraspecific variation in outcrossing rates and sex-specific factors that influence variation in outcrossing rates (including male reproductive senescence).
Danio rerio: The zebrafish system is a powerful model for genetics and vertebrate development. Sex determination in zebrafish is influenced both by genes and the environment. I am working to identify the genes underlying sex determination in this fish.