Research:

As a geneticist and evolutionary biologist, I am intrigued by a broad array of scientific puzzles. My projects are united by my interest in how new combinations of DNA are created and maintained. My work uses genetics to investigate evolutionary questions such as:

• How does variation in chromosomal arrangement shape evolution?
• How does genetic exchange via hybridization and recombination influence adaptation and divergence?
• How does linkage-disequilibrium shape nucleotide variation through the action of linked selection?
• How can we better understand the extent and effects of gene flow, and how can the effects of gene flow be distinguished from those of ancestral polymorphism?

Recombination and inversions:

During my PhD work, one of my primary aims was to understand how chromosomal inversions shape meiotic recombination, the process that shuffles combinations of alleles across loci. Inversions suppress recombination, but we don’t fully understand how and to what extent. Though single-crossover products are prevented within inversion heterozygotes, non-crossover gene conversion (and double crossovers) can still occur. By studying the frequency and distribution of non-crossover gene conversion in inversion heterozygotes, I aimed to improve our understanding of how recombination acts alongside natural selection to influence genome evolution and speciation processes (Korunes & Noor 2017: doi:10.1111/mec.13736).

To better understand the recombination-barrier imposed by inversions, I examined rates of gene conversion in experimental crosses both within Drosophila pseudoobscura and between D. pseudoobscura and its naturally-hybridizing sister species D. persimilis. Through genome-wide empirical analyses of within species and in species hybrids, I observed that gene conversion rates in interspecies hybrids are at least as high as within-species estimates of gene conversion rates, and gene conversion occurs regularly within and around inverted regions of species hybrids, even near inversion breakpoints. This analysis is the first direct empirical assessment of gene conversion rates within inversions of a species hybrid, and these data show that gene conversion has the potential to reduce the efficacy of inversions as barriers to recombination over evolutionary time.

​For more details on this project, see Korunes & Noor 2019 (doi.org/10.1111/mec.14921) or check out my short talk from The Allied Genetics Conference, 2016: How much do chromosomal inversions prevent gene conversion and interspecies gene flow?

Linked selection:

Despite the shuffling of alleles via recombination, alleles at neighboring loci often remain non-randomly associated. This non-random association, or linkage-disequilibrium (LD), has evolutionarily important effects both within and between species. I study genetic diversity in Drosophila species with the goal of disentangling how different selective forces at a given locus can affect genetic diversity at neighboring linked loci. By understanding meiotic recombination and linked selection, I aim to address broader questions about how genetic diversity is created and maintained.

The role of introgression in speciation and divergence:

The sister species pair Drosophila pseudoobscura and D. persimilis present an opportunity to dissect an evolutionary history of divergence nuanced by multiple inversions, lineage sorting, and gene flow. I am using whole-genome sequence data to re-explore patterns of introgression and divergence in the Drosophila pseudoobscura / D. persimilis system, with particular emphasis on signals of possible introgression in the past 150,000 years since the split of the allopatric D. pseudoobscura subspecies, D. pseudoobscura bogotana (D. p. bogotana), from North American D. pseudoobscura (D. p. pseudoobscura). This investigation presents the opportunity to not only examine the effects of introgression, but also to understand how differences in evolutionary rate among lineages can influence patterns of divergence and tests for introgression.