Variation in mating systems is one of the primary determinants of the pattern of genetic variation within plant and animal populations. The cause of these differences, both in terms of proximate genetic changes and ultimate ecological outcomes, is almost completely unknown except in a few specialized cases. This project aims to undercover the genetic basis of mating system variation within the well-studied nematode model system, Caenorhabditis elegans, and to use this information together with predictions from theoretical models to investigate how changing levels of mutational input affect the transition between different forms of sexual reproduction. Mating system genetics will be assessed using high throughput functional genomic approaches, and the predictions will be tested experimentally using direct genetic manipulation of mutation rate and an individual's propensity to produce male offspring.
This research should further our understanding of the mechanisms responsible for generating the tremendous variation in mating systems in both plants and animals. The processes studied here are fundamental to describing variation and change in agricultural and natural systems, especially in endangered species of plants and animals. Nematodes themselves are one of the most numerous, yet understudied, groups of organisms on earth and are important animal and plant pathogens.
Variation in mating systems is one of the primary determinants of the pattern of genetic variation within plant and animal populations, which plays a fundamental role in describing variation and change in agricultural systems (e.g., pest resistance) and natural populations (e.g., endangered species). The causes of these differences, both in terms of their genetic basis and their ecological context, are almost completely unknown except in a few specialized cases. This study used the model nematode species, Caenorhabditis elegans, to address both of these questions. First, the genetic basis of natural variation in reproductive differences was isolated to specific chromosomal regions, which can now be used to identify the underlying genes. Second, experimental tests using populations with different types of mating systems definitively showed for the first time that genetic mixing via outcrossing plays a critical role both in mitigating the impacts of harmful mutations and in allowing populations to adapt to rapidly changing environments. In addition to these scientific impacts, this project helped to train nearly a dozen undergraduate, graduate, and postdoctoral students in advanced research techniques. The results produced in this project were also used as a tool to communicate the excitement of scientific research to the broader population via public outreach seminars.
