An examination of introgression in the Trillium erectum species complex using microsatellite analysis

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Austin William Brenek (Creator)
Western Carolina University (WCU )
Web Site:
Katherine Mathews

Abstract: There are seven named taxa in the Trillium erectum L. species complex native to North America, many of which are experiencing secondary contact and hybridizing due to a lack of reproductive isolating mechanisms. This project will focus on T. erectum var. album, a white-flowered taxon, T. erectum var. erectum, a red-flowered taxon, and T. rugelii, another white-flowered taxon, each of which occurs in the southern Appalachian Mountains in populations that overlap in both geographic distribution and flowering phenology. Using three microsatellite loci developed for a related Trillium sp., this study examines the hybridization and genetic structure of several populations of the T. erectum species complex located in three counties in the western region of North Carolina to determine if the taxa growing in mixed populations are 1) interbreeding and 2) if so, quantify the amount of admixture in each population to examine what factors (taxon identity, geographic range, or flower color) are most influencing hybridization. Allele frequency analyses of microsatellite loci were also used to compare the populations, and Principle Components Analysis was used to make pairwise comparisons of both the fixation index and Nei’s Genetic Distance calculations for each geographic population. Finally, structure analysis was used to identify populations and quantify admixture based on allele frequency and assumptions of gene flow using Bayesian statistical methods. Results from population genetics and genetic structure analyses suggest that allele sharing occurs primarily based on taxon identity and geographic proximity, but flower color may also play a role in influencing gene flow.

Additional Information

Language: English
Date: 2021
Trillium, North Carolina, Appalachian Mountains, Hybridization, Genetic analysis, Microsatellite analysis
Plant hybridization
Microsatellites (Genetics)
Trilliums -- Appalachian Region, Southern -- Genetics

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