Term of Award

Summer 2022

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Biology

Committee Chair

Lorenza Beati

Committee Member 1

Scott Harrison

Committee Member 2

Lance Durden


The Gulf Coast tick, Amblyomma maculatum Koch, 1844 is a known vector of Rickettsia parkeri Lockman, 1965 which causes rickettsiosis. An emerging population in the western U.S. is genetically similar yet morphologically different from the known A. maculatum s. s. population in the East. We analyzed 176 individuals of A. maculatum collected in Arizona, Oklahoma, Georgia, and Florida in 2016 with eight polymorphic microsatellite markers. F-statistics showed that no locus was linked and all but one displayed significant deviation from Hardy-Weinberg equilibrium. The combined loci showed significant heterozygous excess with an FIS value of -0.142 and p-value = 0.0002. Six of the eight microsatellite loci were proven to be useful in determining subpopulation differentiation and evaluating the number of immigrants between the eastern and western regions. The genetic differentiation between the eastern and western populations was calculated with an FST’ = 0.3902, between western sites in Arizona FST’ = 0.0244 and between eastern sites FST’ = 0.0273. The number of individuals to immigrate was calculated to be within 11-37 every 100 generations which is substantially low. The use of microsatellite markers for the study of population structure in A. maculatum s. l. in the U.S. suggests that the western and eastern population could be two different species as indicated by previous crossbreeding experiments.

OCLC Number


Research Data and Supplementary Material