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Population genetic structure and demographic history of the lone star tick, Amblyomma americanum (Ixodida: Ixodidae): new evidence supporting old records

Citation

Lado, Paula; Smith, Megan; Carstens, Bryan; Klompen, Hans (2020), Population genetic structure and demographic history of the lone star tick, Amblyomma americanum (Ixodida: Ixodidae): new evidence supporting old records, Dryad, Dataset, https://doi.org/10.5061/dryad.pk0p2ngjq

Abstract

Range expansions are a potential outcome of climate change. Population genetic structure and demography can be used as tools to evaluate hypotheses on changes in geographic distribution. In this study we explored the genetic variability, population genetic structure, demographic history, and habitat suitability of Amblyomma americanum, a North American tick species that is a known vector of several pathogenic microorganisms. We used a novel double digestion restriction site-associated DNA sequencing (dd-RAD seq), and we discovered 8181 independent single nucleotide polymorphisms (SNPs) from 189 ticks from across the geographic range of the species. Overall, genetic diversity was lower than expected. Further, the edge populations did not have a statistically significant lower diversity than core populations, and hypotheses of range expansion are not supported by a test based on genetic data. Nonetheless, moderate levels of population structure were detected among geographic regions, with the northeast cluster the least variable. Demographic and species distribution models support a scenario where A. americanum was present in more northern locations in the past, underwent a bottleneck, and is now recovering. These findings highlight the importance of demographic modeling and genomic data in assessing the recent history and genetic structure of pathogen vectors.

Funding

National Science Foundation, Award: DEB-1457519