In September, Joanna Kelley traveled to Berlin, Germany to present her work on sulfidic fish at EMBO’s workshop Beyond the standard: Non-model vertebrates in biomedicine. A summary of her talk can be found here.
In an era of unprecedented global change, exploring patterns of gene expression among wild populations across their geographic range is crucial for characterizing adaptive potential. However, few of these studies have identified transcriptomic signatures to multivariate, environmental stimuli among populations in their natural environments. In this study, Fraik et al. identified environmental and sex-driven patterns of gene expression in the Tasmanian devil (Sarcophilus harrisii), a critically endangered species that occupies a heterogeneous environment. No transcriptome-wide patterns of differential gene expression were detected, consistent with previous studies that documented low levels of genetic variation in the species. However, genes previously implicated in local adaptation (Fraik et al. 2019, Biorxiv) to abiotic environment in devils were enriched for differentially expressed genes. Additionally, modules of co-expressed genes were significantly associated with both geographic location and sex. This study revealed that candidate-gene approaches to transcriptomic studies of naturally sampled wildlife populations may be necessary to capture gene expression changes in response to complex multivariate environments.
Fraik, A.K., Quackenbush, C., Margres, M.J., Comte, S., Hamilton, D.G., Kozakiewicz, C.P., Jones, M., Hamede, R., Hohenlohe, P.A., Storfer, A., Kelley, J.L. Transcriptomics of tasmanian devil (Sarcophilus harrisii) ear tissue reveals homogeneous gene expression patterns across a heterogeneous landscape. Genes 2019, 10, 801. *Corresponding author
Saving the Tasmanian Devil, a new book by Dorothy Hinshaw, features Alex’s time in the field in Tasmania studying devil facial tumor disease.
Shawn Trojahn details his work using grizzly bear transcriptomics to compare gene expression in the hibernating versus active phases of a bear’s life.
Various animals have colonized caves, and in the course of evolution, many have lost their eyes. We still do not fully understand how the loss of an entire organ unfolds as organisms adapt to dark caves. In this study, Ph.D. student Kerry McGowan and colleagues examined a small fish, the cave molly, that colonized caves relatively recently and exhibits functional eyes that are reduced in size. Using gene expression analyses, McGowan et al. showed that several eye-related genes are expressed less in cave mollies compared to their surface ancestors. Evolution has modified many of these genes in other completely blind cavefishes, suggesting that cave adaptation may occur in similar fashions.
McGowan KL*, Passow CN, Arias-Rodriguez L, Tobler M, Kelley JL. 2019. Expression analyses of cave mollies (Poecilia mexicana) reveal key genes involved in the early evolution of eye regression. Biol Lett. 15(10):1-7.
*Corresponding author
A cavefish from the Cueva del Azufre system in southern Mexico.
Note the small eye. PC: Michael Tobler.
Congratulations to Dr. Joanna Kelley and Dr. Michi Tobler for received funding for their Rules of Life proposal. The proposal is jointly funded by the NSF Division of Integrative Organismal Systems and Division of Environmental Biology. The grant Extreme Environments, Physiological Adaptation, and the Origin of Species (with Michael Tobler) will fund research on fish that have adapted to sulfidic springs throughout the Americas.
A sulfidic spring in southern Mexico (above).