Whitney Murchison-Kastner
Graduate Student
Tulane University
Ecology and Evolutionary Biology
Posted 6-20-25

Bluesky

Me spotting my first ever Mimulus in the wild, right outside of our field cabin in Yosemite National Park, California.

I am broadly interested in how organisms repeatedly adapt to harsh environments and the genetic traits that enable these adaptations. In particular, I study parallel evolution—how different species evolve similar traits in response to similar environmental pressures.

My dissertation research focuses on two closely related Mimulus species: serpentine-adapted M. guttatus and granite-outcrop-adapted M. lacinatus. Both species are found in harsh, rocky environments with limited water and high temperature fluctuations. Fascinatingly, they have evolved similar traits, such as lobed leaves, early flowering, and red floral spotting. My goal is to determine whether these shared traits result from the same genes (genetic parallelism) or from different genetic mechanisms.

To address these questions, I’m using quantitative trait loci (QTL) mapping on three F2 hybrid populations derived from crosses among serpentine M. guttatus, wet seep M. guttatus, and M. lacinatus. I aim to determine whether differences in genetic architecture across mapping populations are driven by the genetic background of the serpentine or lacinatus parents. Preliminary results suggest that floral spotting is controlled by a single, large-effect locus, while traits like leaf lobing and flowering time likely have more complex genetic architectures.

In addition, I am using pool-sequencing (Pool-seq) to investigate whether specific loci are under selection in lobed versus rounded-leaf individuals in polymorphic serpentine populations of M. guttatus. Together, these projects aim to deepen our understanding of the genetic basis of parallel evolution and how plants adapt to challenging environments. I hope my research will not only illuminate fundamental evolutionary processes but also help us understand how plants may respond to future environmental stressors.

1. My son, Emory, and I hiking outside Colorado Springs.
2. These are some of my F2 hybrid individuals. I made from crossing M. guttatus with M. lacinatus.
They displayed very distinctive- and cute- red floral spots!
3. A picture of one of my field sites, where you can find Mimulus guttatus
growing on serpentine soils at the McLaughlin Natural Reserve in California.

How Whitney got interested in the botanical sciences:

Although I have always enjoyed plants and spent much of my childhood gardening with my parents, I never considered a career studying them. I began my scientific journey focused on animals. As an undergraduate, I worked in a lab studying the phylogenetics of tarantulas. After graduation, I worked as a research technician studying pediatric cancer in zebrafish. I later completed a Master of Science in conservation genetics, where I studied endangered populations of the Greater Prairie Chicken and the Eastern Collared Lizard. It was during this program that I developed a deep interest in evolution and sought an ecologically relevant system to study evolutionary processes in action. Despite having no prior plant research experience, beyond gardening, I applied to a lab that uses Mimulus guttatus to investigate the genetics of adaptation and speciation.

After working in the Mimulus system for over four years, I truly feel I’ve found my scientific home. I love working with plants in the greenhouse, even when it involves caring for and collecting data for over 700 individuals! I also realized that my personal ethics aligned more closely with plant-based research than working with live animals. One of the things I enjoy most is the ability to generate large datasets with robust sample sizes—something not always feasible in animal conservation work. Visiting wild Mimulus populations in places like Yosemite National Park and in Napa and Sonoma Valley has further deepened my connection to these plants and shaped my research questions. Finally, I’ve found the plant science community—especially the Mimulus research network—to be incredibly welcoming and intellectually vibrant, which has helped to reinforce my interest in plant sciences.

My husband and I walked in a Mardi Gras parade called Chewbacchus, I made the
Mimulus costume myself and modeled it after my hybrid plants I had growing in the greenhouse at the time.

Whitney's advice for those just starting their botanical journey:

As someone who didn’t start out as a “plant person,” my biggest advice is: just start! The best way to find out if plant science excites you is to get hands-on experience. Volunteer in a plant-focused lab during your undergraduate career, or get involved with your local botanical society, gardening club, etc. Community events like tree planting days or environmental cleanups are also great ways to get connected.

In high school, I did a lot of outdoor volunteer work, including time at a wastewater treatment facility that used Louisiana’s native ecosystems to filter water. That experience sparked my appreciation for the ecological roles of plants and for teaching others about ecology. I believe it’s essential to recognize how fundamental plants are to our daily lives, not just as research subjects, but as critical components of ecosystems and human well-being.

Finally, if you’re someone who is more question-driven versus focused on a particular organism, consider the kinds of questions you’re most curious about and explore how plants can help you answer them.

 

Whitney's other passions:

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