Analysis of Gene Flow Between Geographically Separated Populations of Etheostoma radiosum in Northeastern Texas and Southeastern Oklahoma

Document Type


Degree Name

Master of Science (MS)


Biological and Environmental Sciences

Date of Award

Spring 2023


The genus Etheostoma has been found to be one of the most cryptic groups in North America today. Many darter species are habitat specialists that have limited dispersal in drainages across unsuitable conditions. Etheostoma radiosum is found in the Red River system of Oklahoma, Arkansas, and Texas, where it is more common in upland tributaries with gravel, indicating that the muddier main stem of the Red River may restrict gene flow patterns between systems. The purpose of this study is to use molecular markers to determine genetic population structure of this species in Texas populations and potential barriers and genetic isolation. We sampled five populations in Texas tributaries and three populations in Oklahoma in different tributary systems in 2022. Captured individuals had caudal fin clips taken in the field, followed by DNA extraction and amplification at six microsatellite loci. Pairwise FST values, observed and expected heterozygosity, STRUCTURE analyses, isolation by distance, and discriminant analysis of principal components were done to determine population genetic patterns in the region. Results indicate the existence of three distinct genetic clusters in the region.


Bjorn Schmidt

Subject Categories

Ecology and Evolutionary Biology | Life Sciences