Shawn K. Thomas
Graduate Student
Biological Sciences
University of Missouri
Posted 3-15-22

Twitter: @shawnkthomas (Twitter/Instagram)

If I had to describe my research in 3 words I would say: Plants, Polyploids, and Pollutants.

Plants because I am working in the family Brassicaceae. Specifically, I am interested in the tribe Brassiceae, which spans everyone's favorite “dogs of the plant world” (Brassica) to weedy coastal plants and odd desert species.

Polyploids because I am super interested in ancient polyploidy in the group. Evidence from previous studies confirms that the core Brassiceae (Brassica and some closely related genera) shares an ancient hexaploidy and diverged from the rest of the Brassicaceae around 9-28mya. However, it is unknown if the ancient hexaploidy is shared only in the core Brassiceae or the whole tribe as currently circumscribed. Furthermore, there is uncertainty with dating the group as fossils in the Brassiceae and Brassicaceae are questionable. I am combining genomic data from across the tribe and robust fossil calibrations in the Rosids, to place and date this ancient polyploid event.

Pollutants because I am interested in abiotic stress caused by soil pollutants. Cakile maritima (European searocket), a halophyte within Brassiceae, has been shown to tolerate both salt (NaCl) and the heavy metal cadmium (Cd). It is hypothesized that mechanisms to tolerate salt may generally overlap with mechanisms to deal with heavy metals. So I am using searocket to explore the mechanisms of salt and heavy metal tolerance and any potential interaction between these mechanisms. Furthermore, I would like to see if the ancient polyploidy in Brassiceae influences abiotic stress tolerance of Cakile and the group as a whole.

How Shawn got interested in the botanical sciences:
For most of my life I was affected by Plant Awareness Disparity (aka Plant Blindness). I didn’t see or really ever think about plants. Only during junior year of undergrad did I realize that #PlantsAreCoolToo. I took a class called “Flowers” with Dr. Shu-mei Chang and shortly after took a Bioinformatics class with Dr. Jim Leebens-Mack. Through these classes I became fascinated with the evolutionary history of plants, genomics and phylogenetics. I was interested in learning more, so I joined the lab of Dr. Jim Leebens-Mack as an undergraduate researcher. My independent research focused on analyzing target enrichment data to reconstruct relationships within dogwoods (Cornus) and other closely related species. After graduating, I stayed on for a year to gain more research experience. My project on dogwoods expanded to include the order Cornales as a whole, and I took on other projects focused on developing bait sets for orchids (Orchidaceae) and conifers. Now I am a PhD student at the University of Missouri working on exploring ancient polyploidy and abiotic stress in the mustard family (Brassicaceae).

Shawn's advice for those just starting their botanical journey:
Get involved in a lab and don’t be afraid to ask for help!

Other Passions:
From pourovers to espresso, I am really passionate about coffee. I am a self-proclaimed coffee snob and love spending time learning all things coffee. I enjoy trying new coffees from all over the world and tinkering with brew settings to get the best possible cup. Other than coffee, I dabble a bit into tabletop games like DnD and some video games. I also enjoy hanging out with friends and exploring nature.

Published Articles in BSA Journals:

Comprehending Cornales: phylogenetic reconstruction of the order using the Angiosperms353 probe set; American Journal of Botany 108(7): 1112-1121. 2021.

Target sequence capture in orchids: Developing a kit to sequence hundreds of single‐copy loci; Applications in Plant Sciences 9(7): e11416.

The best of both worlds: Combining lineage‐specific and universal bait sets in target‐enrichment hybridization reactions; Applications in Plant Sciences 9(7): e11438.

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