1st Place: D3011: Using ancient DNA to identify past ranges of Rhipicephalus sanguineus lineages in Arizona

Rhipicephalus sanguineus sensu lato, commonly known as the brown dog tick (BDT), is a local vector of Rocky Mountain spotted fever (RMSF) in Arizona. Rhipicephalus sanguineus s.l. is comprised of several genetically distinct lineages. Two of these lineages, known as “tropical” and “temperate,” are sympatric in Arizona, although previous data has shown that the “tropical” lineage is a recent arrival to the state (Villarreal et al. 2018). Differences between lineages may be important in terms of disease transmission. Researcher will use archived ticks to gather data on the past distributions of BDT lineages in the state. Available specimens are alcohol-preserved Rhipicephalus sanguineus specimens in the University of Arizona Insect Collection, collected in multiple counties between 1939-1954. Researcher will extract DNA using a nondestructive protocol, and identify individuals to lineage using an established polymerase chain reaction assay using the 12S mitochondrial gene (Brophy). Data will then be compared to the current known ranges of “tropical” and “temperate” BDT in Arizona. This study will demonstrate any changes in range for these lineages over time, which may have significance for outbreaks of RMSF in Arizona seen in the early 21^st century. Understanding the ranges of medically important vectors is vital for developing control programs and predicting future outbreaks.