The magnum opus chapter of Matthew’s dissertation reports on the mechanisms that underpin reproductive disorders in Lake Apopka female alligators (the paper can be found linked here). This lake is contaminated with endocrine disrupting chemicals that have the potential to interact with the estrogen receptor and the Lake Apopka alligator population has been used as a model for understanding environmental reproductive health since the early 90’s. We found that approximately ¾ of genes are differently expressed in Lake Apopka alligator ovaries when compared to a reference site. The big surprise was that exposing embryos from the reference site to a single dose of estrogen (prior to ovarian differentiation) was sufficient to overwhelmingly recapitulate these patterns. Also noteworthy is this estrogen treatment in reference animals also recapitulated the follicle abnormalities in Apopka ovaries. Our main conclusion is that estrogenic contaminants are likely disrupting the timing of estrogen signaling during ovarian differentiation, which leads to persistent changes to ovary structure and function that are apparent long after the initial exposure. Chris Smaga, a new graduate student in the lab, is following up on these questions, so stay tuned!
Samantha is tracing how climatic factors weave their way through developmental processes to influence organismal form, function, and survival. Her dissertation projects truly represent the integrative nature of our group and include monitoring/modelling alligator nest temperatures, investigating how thermal signals are integrated into sexually dimorphic epigenomes, and now trying to assess the influence of all these factors on survival! Like most of the projects in our lab, this takes a team effort and Samantha recently assembled a ‘super team’ to help with a hatchling roundup. This included grad students Emily, Laura and Kristen, along with SCDNR biologists Joseph and Mark, and of course, Thomas Rainwater from the Yawkey Wildlife Center and Clemson University. Good times!
We are thrilled to welcome Chris Smaga and Josiah Johnson to the lab! Chris earned his undergraduate degree from SIU where he studied snake fungal disease. In the Parrott Lab, Chris will be investigating the developmental origins and pathways underlying epigenetic variation across natural populations of alligators. Josiah hails from Colby College where he focused on advancing Northern black racer conservation. Josiah is planning to study how life history traits and reproductive development vary across amphibian communities along a contaminant gradient of Carolina Bays. Welcome guys!!
Yeraldi is doctoral student in Shane Campbell-Staton's lab at UCLA and is collaborating with us this summer. Samantha and Yeraldi are interested in discovering the determinants of alligator hatchling survival and how these traits are influenced by environment-by-embryo interactions during development. I don't want to give away any spoilers, but this project is HUGE! We are super excited to have Yeraldi at the lab-- welcome Yeraldi!!
The lab was recently awarded a NSF grant to investigate how epigenetic aging dynamics interact with ecological and environmental factors to affect organismal function and variation in life history traits. This work will build on Emily's work using the medaka fish model to develop epigenetic aging clocks. We will be recruiting undergraduates, graduate students, and a postdoc, so keep an eye on the opportunities page or reach out to Ben (firstname.lastname@example.org) if interested!
With the help of awesome collaborators and friends, Laura was able to get a nice start on her masters project examining how environmental contaminants affect behavior and movement and conversely, how does animal movement influence the way in which contaminants are distributed across the landscape! Laura has posted updates (with nice pictures) on our lab twitter account (@lab_parrott). Beyond everyone in our lab and awesome co-investigator Tracey Tuberville, Thomas Rainwater (Clemson, mask below) and Kurt Buhlmann (see below) have been especially generous with their time and expertise!
Excellent work Samantha! Congratulations!
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.