2.b.i. Genetic structure relative to geographic regions
Researchers have been studying the variation of I. scapularispopulations by identifying phenotypes that vary geographically and correlate with human Lyme disease prevalence (Arsnoe et al., 2019, Ginsberg et al, 2014). Questing height has been demonstrated to be correlated with population origin via common garden experiments, remaining correlated in subsequent generations, thus supporting the notion that this important host-seeking behavior has one or more genetic drivers (Arsnoe et al., 2019). However, genotypes or a genomic region of interest have not yet been linked to these phenotypes. Thus, a major goal of this study was to develop a foundational database of genetic variants in I. scapularis populations that are located throughout the genome and can potentially be used in future studies to link genotypes to phenotypes of interest.
Genetic structure was originally analyzed through the lens of the four geographic quadrants (Figure 1). Differentiation is modest when comparing the Northeast to Upper Midwest or comparing the Southeast Atlantic to Southern Gulf. However, outside of the population originating from Osceola County, Florida, most genetic differentiation occurred in comparisons of Northern populations to Southern populations. These two major classifications can simplify the lens for how these results are viewed and mirrors the original delineation between I. scapularis and I. dammini .