NAU Post-Doc Has Sequenced the Genome of the Spotted Bat

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Faith Walker uses a minimally-invasive genetic sampling method involving buccal swabs to collect DNA from live captures such as this spotted bat, which was later released. Photo: Brian Keeley.

Faith Walker, NAU postdoctoral research associate working with Professor Carol Chambers in the School of Forestry, has successfully sequenced the genome of the spotted bat. Using low-coverage, next-generation sequencing techniques, Walker and colleagues from The Center of Microbial Genetics and Genomics identified genetic regions called microsatellites that are highly variable, even between individuals. This is a breakthrough for this charismatic yet hard-to-capture species and will allow Chambers and Walker to examine population characteristics, which are typically not well-known in bats in general but especially for this species. One way to count bats is to use genetic information to estimate population sizes.

According to Walker, population information is useful for land managers. For example, it helps them set acceptable mortality thresholds for such projects as wind-turbine development. These thresholds are meant to rein in potential wildlife losses. Currently, they are primarily based on perception.

The next step is to test several dozen microsatellites (short segments of DNA that have a repeating sequence) to see which are best for differentiating between individuals and for characterizing genetic diversity. This is the same approach used in forensics, but instead of a bat-whodunit search, this is a case of understanding a secretive species. These tools allow researchers to determine relatedness between individuals as well as relatedness among populations of individuals. Screening DNA samples over time and across great distances using microsatellite and mitochondrial markers adds additional information. “When we look at genetics, we can see how the lineage has changed over time and space,” says Chambers. Extending the reach of sampling into Mexico and British Columbia, for example, adds information about how much movement there has been between regions.

To analyze the species as thoroughly as possible, the study will involve sampling living, historical, and mummified bats, some of which are hundreds of years old. One mummified sample goes back 10,000 years.  Walker will be traveling to the Smithsonian Institution in Washington, DC, to extract DNA from the museum’s bat collection.

--Sylvia Somerville