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Jennifer M. Dechaine
Associate Professor
Department of Biological Sciences / Department of Science Education
Central Washington University
No Bats in the Belfry: The Origin of White-Nose Syndrome in Little Brown Bats

This interrupted case study investigates the geographic origin of white-nose syndrome (WNS) in little brown bats (Myotis lucifugus). WNS is a devastating fungal disease caused by the fungus, Pseudogymnoascus destructans (formerly known as Geomyces destructans), which has led to the death of over 5 million bats in the United States since 2006 and continues to spread. Specifically, the case uses the scientific process to dissect the Warnecke et al. (2012) study published in the Proceedings of the National Academy of Sciences suggesting that the strain of P. destructans causing WNS in North America is an invasive fungal species from Europe. The case format focuses on scientific process skills, such as developing hypotheses, designing experiments, and drawing and interpreting quantitative data. The case also provides an opportunity to discuss coevolution and the evolutionary "arms race" that can occur when a host species evolves resistance to a disease and then the pathogen evolves new ways to infect the host. The case was developed for a non-majors undergraduate biology course but could also be used in any level of college biology or potentially advanced high school biology.

The Evolving Genetics of Disease Resistance 

This interrupted case study for the flipped classroom applies evolutionary genetics research to human health. Students learn about a naturally occurring, but rare, allele of the CCR5 gene, CCR5-Δ32, which provides resistance to HIV. They use data from primary literature sources to predict and interpret worldwide patterns of CCR5-Δ32 frequency distribution. They then discuss how these allele frequency patterns may have been driven by selection imposed by various diseases or by other evolutionary mechanisms. Next, they test published data using Hardy-Weinberg equilibrium to examine if CCR5-Δ32 also provides genetic resistance to West Nile virus. Finally, they complete a jigsaw discussion of Nature News articles that report on how CCR5 research is being used to develop therapies to treat HIV. Originally written for the evolution portion of a yearlong biology series for undergraduate majors, the case is also appropriate for some non-majors biology courses or, with added complexity, upper-level evolution, genetics, or cell biology courses.