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Date of Award
Winter 2024
Rights
Access perpetually restricted to EWU users with an active EWU NetID
Document Type
Thesis: EWU Only
Degree Name
Master of Science (MS) in Biology
Department
Biology
Abstract
Lichens are long-lived, sessile symbiotic assemblages of fungi, algae, and bacteria, often exhibiting a high incidence of rarity. As an emergent trait, rarity encompasses the complexities of a species’ life-history traits and its environment. Using a comparative framework, we examined the population and landscape genetic patterns associated with rarity in related widespread and range-restricted lichenized fungi sampled throughout the Appalachian Mountains of eastern North America. This research produced robust genomic datasets for widespread species (Punctelia rudecta, Lepraria finkii, and Usnea strigosa) and rare congeners (P. appalachensis, L. lanata, and U. subfusca), totaling 924 individuals from 36 sites – one of the largest population genomic datasets for lichenized fungi produced to date. Using a suite of bioinformatic tools, short-read sequences produced using whole-genome shotgun sequencing (WGS) were aligned to reference genomes, assembled from long-read sequencing, and filtered for quality before downstream analyses. The novel pipeline developed for this research advances established workflows for assessing high-volume population-level WGS datasets from complex metagenomic data. Comparisons of population genetics between range-restricted and widespread species established similar patterns of gene flow and genetic differentiation for both species groups. Range-restricted species generally exhibited greater genomic distances between multi-locus genotypes with less admixture between populations than widespread species. Mantel tests identified isolation-by- distance only in range-restricted species highlighting the influence of geographic distance on genetic distance in that group. Distance-based redundancy analyses revealed isolation-by-environment in all species studied indicating that variation in environmental variables associated with climate and habitat quality influences genetic distances in both range-restricted and widespread species. These findings underscore the role of geographic distance and habitat factors in shaping population and landscape genetic patterns associated with rarity in lichenized fungi.
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Sharrett, Stephen T., "Rarity, cause or consequence: comparative landscape genomics of six lichenized fungi with contrasting range sizes, life histories, and morphologies" (2024). EWU Masters Thesis Collection. 948.
https://dc.ewu.edu/theses/948
