RESEARCH
Developmental Plasticity and Environmental Change
Interactions between developing embryos and their environment have profound consequences for organismal form and function later in life. One of the starkest examples of this phenomenon is temperature-dependent sex determination (TSD), where the temperature an embryo experiences during a discrete period of development determines whether it will develop an ovary or testis. TSD occurs in a range of species including many turtles, all crocodilians, and some fish. This research uses TSD as a model to explore how dynamic environmental factors shape lasting patterns of phenotypic variation. We ask questions like:
- How do embryos interpret fluctuating environmental signals to produce alternate developmental outcomes?
- How do these developmental decisions influence subsequent individual fitness?
- What ecological and evolutionary factors shape the developmental environment?
- How and why do individuals, populations, and species vary in their developmental responses to the environment?
To address these questions, we use a combination of approaches from field ecology, developmental biology, and genomics. This work seeks to reveal fundamental biological principles governing plasticity while also informing predictions about population resilience in the face of rapid environmental change.
Selected Publications:
- Parrott, B.B. & Bock, S.L. (2025). An epigenomic threshold hypothesis for integrating dynamic environmental signals into functional models of developmental polyphenisms. Functional Ecology. https://doi.org/10.1111/1365-2435.70099
- Bock, S.L. et al. (2023). Differential early-life survival underlies the adaptive significance of temperature-dependent sex determination in a long-lived reptile. Functional Ecology, 37(11), 2895–2909. https://doi.org/10.1111/1365-2435.14420
- Bock, S.L. et al. (2020). Post-transcriptional mechanisms respond rapidly to ecologically relevant thermal fluctuations during temperature-dependent sex determination. Integrative Organismal Biology. https://doi.org/10.1093/iob/obaa033
- Bock, S.L. et al. (2020). Spatial and temporal variation in nest temperatures forecasts sex ratio skews in a crocodilian with environmental sex determination. Proceedings of the Royal Society B, 287. https://doi.org/10.1098/rspb.2020.0210
Evolution and Plasticity of Aging Trajectories
Aging is nearly universal, yet individuals and species vary widely in how long they live and the degree to which their health declines with age. Growing evidence links this variation in aging to processes occurring in early life, however, the mechanisms connecting development and aging remain largely unresolved. This work focuses on how the epigenome, the layer of chemical modifications that control gene activity and genome stability, bridges these processes. To uncover links between the environment, the epigenome, and patterns of aging, this work harnesses the diversity of life history strategies employed by fishes and reptiles. In particular, we study cartilaginous fishes (e.g., sharks, skates, and rays), species that vary widely in their reproductive strategies, developmental rates, and lifespans, to test the molecular and evolutionary drivers of aging variation across species. Within species, we’re also interested in understanding how variable sex determination systems contribute to sex-specific aging patterns in reptiles.
Selected Publications:
- Bock, S.L. et al. (preprint). Widespread sex-biased gene expression reflects female-biased longevity in a species with environmental sex determination. bioRxiv. https://doi.org/10.1101/2025.11.26.690843
- Rayner, J.G. et al. (2025). Sex differences in DNA methylation in bats. Annals of the New York Academy of Sciences. https://doi.org/10.1111/nyas.70021
(Epi)genomic Tools for Conservation
Conservation requires demographic insight, but for many species, gathering data on sex and age in wild individuals can be challenging. For example, in species with temperature-dependent sex determination, environmental change threatens to skew population sex ratios. However, early life stages of these animals often lack sexually dimorphic traits, impeding efforts to monitor sex ratios in the wild. Age distributions serve as another key population metric for wildlife managers, but assessing the ages of wild individuals remains difficult. Methods of determining age are often inaccurate (e.g., size-based metrics) or require destructive sampling (e.g., skeletochronology, otoliths). This research uses epigenomic techniques to develop molecular biomarkers of age and sex that can be measured from minimally-invasive samples (e.g., blood). Ultimately, this work seeks to provide actionable genomic tools for use in conservation management contexts.
Selected Publications:
- Bock, S.L. et al. (2026). Genome-wide DNA methylation patterns predict age in the zebra shark (Stegostoma tigrinum) and provide insight into the evolution of vertebrate aging. Molecular Ecology, 35, e70326. https://doi.org/10.1111/mec.70326
- Bock, S.L. et al. (2022). Genome-wide DNA methylation patterns harbor signatures of hatchling sex and past incubation temperature in a species with environmental sex determination. Molecular Ecology, 31, 5487–5505. https://doi.org/10.1111/mec.16670