Abstract
Conservation successes for the endangered Indiana bat (Myotis sodalis)
in the early 2000s were largely reversed by white-nose syndrome (WNS), a
novel fungal disease that emerged in North America in 2006. Impacts have
been variable among Indiana bat colonies, but many maintain negative
population growth, leading to concern for their long-term viability.
Adaptive evolution (i.e., evolutionary rescue) could allow populations
to persist despite disease, as has happened for other species; however,
the evolutionary potential of Indiana bats remains unclear. Here, we
perform a genome-wide scan to test for signatures of selection by
comparing bat tissue samples from five geographic regions before and
after WNS emergence. We tested for three types of selection across
geographic scales: 1) selection targeting different genetic loci in
different geographic regions; 2) parallel selection targeting similar
loci range-wide; and 3) parallel selection affecting subsets of
geographic regions. Our results suggest widespread evidence for
selection in Indiana bats that varies by geographic region, implying
differences in standing genetic variation or context-dependent WNS
responses. We provide evidence for stabilizing and directional selection
acting within individual geographic regions and in parallel within
subsets of geographic regions. However, we detected no evidence of
parallel selection acting on the same genomic coordinates across all
geographic regions. Taken together, our results suggest selection in
Indiana bats is driven in part by environmental factors that vary by
geographic region or hibernaculum in addition to WNS.