Date of Award
8-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Plant and Environmental Science
Committee Chair/Advisor
Dr. Norman Wickett
Committee Member
Dr. Michael Caterino
Committee Member
Dr. Christopher Parkinson
Abstract
Mosses are the second most species-rich group of land plants. They represent a critical group for understanding the evolution and diversity of land plants. Mosses comprise two major groups, acrocarps and pleurocarps. Despite having a more recent evolutionary origin than acrocarps, pleurocarps are exceptionally diverse. The difference in species richness reflects a rapid species diversification, roughly coincident with the origin and diversification of flowering plants. The speciation events giving rise to pleurocarp diversity happened so rapidly, making it historically difficult to produce strongly supported phylogenies with which to test evolutionary hypotheses. One such hypothesis is whether large-scale changes at the genome level contributed to the rapid diversification of pleurocarps. Genome duplication has been implicated in the origin and speciation of other plant groups. To identify whether whole genome duplication (WGD) events coincided with the species diversification of pleurocarps, we used transcriptomes to reconstruct the number of individual gene duplication events in the inferred ancestor of pleurocarps and determined whether these duplicated genes were biased towards specific functions. We built a species tree including 14 acrocarps and 64 pleurocarps upon which gene duplications and losses inferred from gene trees were placed. We found that the rapid speciation of pleurocarpous mosses may not have been the direct result of a WGD event but rather smaller gene duplication events over time. The results reveal some candidate genes and associated pathways coincident with the transition from acrocarps to pleurocarps, suggesting that WGD was not instrumental in the evolution of pleurocarps.
Recommended Citation
Cobb, Meredith A., "Association Between Gene Family Expansion and the Rapid Diversification of Pleurocarpous Mosses" (2025). All Theses. 4581.
https://open.clemson.edu/all_theses/4581