Congrats to both Samantha and Emily who were awarded grants from the Odum School of Ecology to further their dissertation research. Samantha will work to empirically address theory regarding why alligators evolved the ability to use incubation temperature as a means to determine sex. Emily will be exploring how the developmental timing of environmental experiences and subsequent endocrine responses influence the process of epigenetic aging.
New paper from our team published in Science of the Total Environment. Emily Bertucci led the project with lots of help from Marilyn. This is particularly exciting for us as it is our first paper using the medaka fish model. Medaka are small fish (with small genomes) that do quite well in our outdoor mesocosm arrays and the system has a lot of genetic resources available. The work is focused on laying the groundwork for environmental influences on biological aging. We first investigate the impacts of chronic exposure to low doses of ionizing radiation on the hepatic transcriptome and then ask if the effects are mediated by systemic/global shifts in the DNA methylome. Ionizing radiation is an interesting environmental factor because all life shares an evolutionary history with radiation and has evolved mechanisms to deal with it, but contemporary exposure (and exposure risk) is higher due to anthropogenic activity. How do adaptive mechanisms that evolved to respond to 'background' levels protect against higher levels over long periods of time? What are the costs? More to come...
New paper from the lab out in Proceedings B (linked here). Was a great collaboration led by Samantha Bock from our lab and Russel Lowers at the Kennedy Space Center. Also Thomas Rainwater and Phil Wilkinson were critical to the nest monitoring work at Yawkey Wildlife Center, and John Drake (Odum School of Ecology, UGA) and Eric Stolen (Kennedy Space Center) helped with the modeling approaches.
We monitored alligator nests across sites and years, and then modeled the influence of climatic and ecological factors on nest temperatures. Incubation temperature determines the sex of hatchlings in crocodilians (and of course many other non mammalian vertebrates). Using this model, we then predicted how nest temperatures and sex ratios will change (or are already changing) in the not too distant future. There's also a lot of interesting basic ecology regarding the nesting environment that shapes these phenotypic trajectories, but the take home is that sex ratios will likely change dramatically in the coming years. However, predicting exactly how is challenging due to the ultra steep reaction norms between incubation temperature and sex ratios. We really need to be monitoring hatchling sex ratios in natural populations because if sex ratios skews can lead to population persistence.
Laura hails from UC Davis, where she earned her Bachelors degree in Wildlife, Fish, and Conservation Biology. She has researched the influence of salinity tolerance on Western Pond Turtle Biology, and more recently has focused on the conservation of Giant Gartersnakes. In the Parrott Lab, Laura is interested in addressing how contaminants impact animal movement as well as how animals might transport contaminants across the landscape.
Had the opportunity to give a guest lecture on ecological influences on developmental biology to undergrad Dev Bio class. Brought along a friend, saying hey (image) to Scott Dougan.
Emily was recently awarded the Erlanger Fellowship, which will support her work on biological aging and the proximal mechanisms underlying environmental-mediated variation in life histories. Samantha was awarded funds from the IUCN-SSC Crocodilian Specialist Group to support her work on developing minimally invasive epigenetic markers of sex in hatchling alligators. Super proud and excited for their work to be recognized (and supported)!
Matthew Hale defended his doctoral work in May and is finishing up work in the lab before starting a postdoc with Bob Cox's group at the University of Virginia in the fall. Congratulations Dr. Hale! Pictured is Matthew with the incredible (wood burned) piece that Marilyn made!
This spring, Stacey Lance and I co-instructed a course on EcoDevo and Ecotoxcology, with meetings on campus and a four-day workshop at the Savannah River Ecology Lab. I immensely enjoyed all our discussions ranging from life-history strategies in amphibians to environmental sex determination in fish. Looking back, I continue to be amazed by the apparent ease in which undergrads were able to digest recent papers and identify critical questions being addressed as well as outstanding questions in the field. Plus, the presentations at the end of the workshop were stellar! Looking forward to next time (Spring 2021).
Josh Zajdel successfully defends his Masters thesis on mating dynamics and population genetics in American alligators!
Findings from Matthew Hale's dissertation work were recently published in Biology of Reproduction, "Embryonic estrogen exposure recapitulates persistent ovarian transcriptional programs in a model of environmental endocrine disruption"