Sponsor
Portland State University. Department of Biology
First Advisor
Mitch Cruzan
Term of Graduation
Summer 2020
Date of Publication
8-11-2020
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Biology
Department
Biology
Language
English
Subjects
Ranunculus -- Oregon, Hybrid zones, Phenotype
DOI
10.15760/etd.7450
Physical Description
1 online resource (vi, 56 pages)
Abstract
Plants pose a well-known challenge to the biological species concept because hybridization is a common occurrence. Range dynamics have a crucial role in determining whether species are given the opportunity to interbreed or not. Successful hybridization can be of particular concern when considering range-limited species and their persistence. In my thesis research, I examine the apparent hybrid zone between the southern Oregon endemic Ranunculus austro-oreganus, a candidate threatened species due to its limited range, and its widespread congener, Ranunculus occidentalis, whose range spans from California to Alaska. The discovered contact zone was recognized in populations which contained apparent intermediate ventral petal coloration phenotypes. First, I utilized morphological quantification to understand phenotypic variation. Phenotype quantification based on ventral petal coloration and leaf trichome density have confirmed the presence of intermediate populations. Second, I confirmed extensive introgression through nuclear genome surveys with Genotyping-by-Sequencing despite structure analyses indicating the presence of two genetic subgroups. Third, 50 outlier loci were analyzed across geographic clines where results suggest the width of the hybrid zone spans 20km. Sampled populations of R. austro-oreganus and R. occidentalis display evidence of extensive, ongoing gene flow and this species complex provides a unique example of genetic exchange between variable phenotypes.
Rights
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Persistent Identifier
https://archives.pdx.edu/ds/psu/33994
Recommended Citation
Persinger, Jessica, "Battle of the Buttercups: Investigating Hybrid Zone Dynamics in a Ranunculus Species Complex" (2020). Dissertations and Theses. Paper 5578.
https://doi.org/10.15760/etd.7450