Utilizing disease surveillance to examine gene flow and dispersal in white‐tailed deer

Abstract

Summary 1.The prevention and management of transmissible diseases hinges upon understanding host dispersal because it influences distribution of wildlife, affects the rate of disease transmission, and alters the spatial distribution of infection. The relationship between host dispersal and chronic wasting disease (CWD) in cervids is of interest because potential interspecies transmission of fatal prion diseases creates serious risks for wildlife, domestic species, and humans. 2. We used molecular techniques to examine dispersal in a population of Illinois white-tailed deer Odocoileus virginianus. Sampled individuals inhabited areas with confirmed cases of CWD, a transmissible prion disease of cervids, with additional sampling in uninfected locations. We genotyped 1410 deer harvested through CWD surveillance using 10 microsatellites and measured gene flow, determined population structure and quantified gender-specific differences in dispersal. Additionally we used spatial autocorrelation and parentage assignments to examine individual movements. 3. Female deer demonstrated philopatry as evidenced by higher levels of genetic structure, positive spatial autocorrelation and maternity assignments within one home range. 4. Male deer were less genetically structured and frequently exchanged genes across >100 km. 5. Synthesis and applications. Dispersal contributes to the spread of wildlife diseases. Therefore, knowledge of wildlife movement patterns can enhance the efficacy of disease control programmes. Our findings show that samples collected for disease surveillance are useful for measuring gene flow and inferring dispersal in white-tailed deer. High genetic admixture indicates males disperse regardless of landscape features. In contrast, distinct clustering of females demonstrates localized dispersal and philopatry. Taken together, results suggest that CWD surveillance and culling of males should be broadly expanded after an outbreak. Furthermore, surveillance of hunter-harvested deer can be used to identify locales in which CWD occurs, and this information should be used to focus culling efforts on females within genetically defined clusters ('matriarchal groups'). Removal of matriarchal groups at those locations will reduce horizontal transmission more than widely distributed population reductions.

The walk is never random: subtle landscape effects shape gene flow in a continuous white‐tailed deer population in the Midwestern United States

“…Our results, however, contrast with those of Kelly et al. (2010), who found significant population substructure for a study area of similar size, including a portion overlapping our study area in north‐central Illinois.…”

Microsatellites behaving badly: empirical evaluation of genotyping errors and subsequent impacts on population studies

“…This is contrary to suggestions of Takezaki and Nei (1996) and DeYoung et al (2003b) that 50 individuals are sufficient for estimating population allele frequencies. While 50 may suffice for genetically homogeneous populations, our deer population was highly mobile and genetically admixed (Kelly et al, 2010). Simulation studies have supported these results by demonstrating that sample sizes <100 are unlikely to produce reliable estimates of population allele frequencies (Rao, 2001).…”

“…BM848 required N = 200 and BM6506 required N = 400 before HWE deviations became significant. The differences in F IS that we observed at varying sample sizes were not likely attributable to population substructuring because the sampled population is not genetically structured at this spatial scale (Kelly et al, 2010). Rather, our results reflect an inability of small sample sizes to capture the range of genetic variation in our population.…”

“…Previous genetic analyses conducted in this area revealed extensive deer movement and extremely low genetic structure, suggesting a single large population (Kelly et al, 2010).…”

Trash to treasure: assessing viability of wing biopsies for use in bat genetic research

“…Given the complexities involved with sampling bat populations, tissues collected for fungal detection represent a valuable genetic resource. Although molecular approaches require intensive sampling efforts, they allow researchers to ask new questions at resolutions previously unavailable (Kelly et al 2010;Green et al 2014). This research will pave the way for interdisciplinary partnerships to increase the knowledge produced from a single sample and for molecular approaches to enhance our understanding of WNS ecology (Archie et al 2009).…”