This study addresses the influence of biotic and abiotic processes on the generation of genetic variation through meiotic recombination. Meiotic recombination can be influenced by environmental and physiological conditions, however we do not know how this plasticity affects recombination rate evolution over time. Sequence-based genotyping methods will be used to survey recombination rate plasticity in response to heat stress at a fine-scale along the entire genome of the fruit fly, Drosophila pseudoobscura. These empirical data are crucial for understanding how recombination rates evolve in changing environments. The results of this work will break new ground in assessing if changes in recombination are adaptive and to what extent those changes have directional effects on the rate of evolution. In addition, undergraduates and graduate students, including those from underrepresented groups will be trained in bioinformatics.
Previous studies of environmentally-induced changes in recombination rate have used visible mutants. In this study, several high resolution sequencing methods will be combined with novel bioinformatic approaches to provide a genome wide map of meiotic crossovers. The first aim is a detailed map of recombination rate variation as a function of heat stress. The second aim is to assess the longer-term evolution of recombination rates and divergence in response to the short term, plastic responses. Ultimately, this research will test the hypothesis that plasticity explains some proportion of genetic signatures of recombination differences within and between species. If supported, this hypothesis would challenge the validity of linkage disequilibrium-based estimates to capture recombination rate evolution. Evolutionary theory currently suggests that environmental changes can affect population genetic signatures of diversity and divergence; this study would directly evaluate this question with empirical data.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
