01 - Microsatellite-based population genetic analysis of Amblyomma maculatum in SE Virginia
Description/Abstract/Artist Statement
The Gulf Coast tick, Amblyomma maculatum, is expanding northwards along the US East Coast, with recent introductions in New York and Connecticut. The expansion of A. maculatum is medically relevant because it is a principal vector of Rickettsia parkeri, the causative agent of human R. parkeri rickettsiosis, which exhibits similar but less severe symptoms than Rocky Mountain Spotted Fever. Newly established populations of A. maculatum have higher prevalence of R. parkeri than those in the historical range, potentially increasing human risk. Gulf Coast ticks move across the landscape via their hosts, which include birds and small mammals for juvenile stages, and large animals for adults; however, the hosts primarily responsible for dispersal are largely unknown. Positive correlation of genetic to spatial distance may suggest short distance dispersal (e.g. via small mammals), whereas no correlation may suggest long distance dispersal (e.g. via migratory birds). Here we apply high-resolution microsatellite markers to examine relatedness of tick populations in southeastern Virginia. Global FST indicated significant structure among sampled populations [FST 0.036; 95%CI (0.27-0.43)]. This finding should be treated with caution, as there was reduced heterozygosity across all subpopulations [FIT 0.14; (0.03-0.24)], suggesting nonrandom mating and deviation from Hardy-Weinberg equilibrium. Pairwise FST indicated small but significant differences in genetic structure among the majority of sample sites. These findings indicate genetic differences among closely separated populations, suggesting long-distance dispersal and supporting previous results of mitochondrial DNA-based studies in this system.
Faculty Advisor/Mentor
David Gauthier
Faculty Advisor/Mentor Department
Biological Sciences
College Affiliation
College of Sciences
Presentation Type
Poster
Disciplines
Molecular Genetics | Population Biology
01 - Microsatellite-based population genetic analysis of Amblyomma maculatum in SE Virginia
The Gulf Coast tick, Amblyomma maculatum, is expanding northwards along the US East Coast, with recent introductions in New York and Connecticut. The expansion of A. maculatum is medically relevant because it is a principal vector of Rickettsia parkeri, the causative agent of human R. parkeri rickettsiosis, which exhibits similar but less severe symptoms than Rocky Mountain Spotted Fever. Newly established populations of A. maculatum have higher prevalence of R. parkeri than those in the historical range, potentially increasing human risk. Gulf Coast ticks move across the landscape via their hosts, which include birds and small mammals for juvenile stages, and large animals for adults; however, the hosts primarily responsible for dispersal are largely unknown. Positive correlation of genetic to spatial distance may suggest short distance dispersal (e.g. via small mammals), whereas no correlation may suggest long distance dispersal (e.g. via migratory birds). Here we apply high-resolution microsatellite markers to examine relatedness of tick populations in southeastern Virginia. Global FST indicated significant structure among sampled populations [FST 0.036; 95%CI (0.27-0.43)]. This finding should be treated with caution, as there was reduced heterozygosity across all subpopulations [FIT 0.14; (0.03-0.24)], suggesting nonrandom mating and deviation from Hardy-Weinberg equilibrium. Pairwise FST indicated small but significant differences in genetic structure among the majority of sample sites. These findings indicate genetic differences among closely separated populations, suggesting long-distance dispersal and supporting previous results of mitochondrial DNA-based studies in this system.