Current projects

Genomic mechanisms linking early-life environments to health

Across mammals, early-life adversity is associated with poorer health, increased mortality, and altered reproductive function. Yet, we still know surprisingly little about the biological mechanisms that connect early-life experiences to these later-life outcomes—or the evolutionary forces that have shaped these sensitivities. Our research investigates how social and ecological experiences across the life course become biologically embedded to influence health, reproductive function, and evolutionary fitness. To do so, we integrate long-term anthropological field data from human and non-human primate populations with genomic analyses of biological tissues and targeted cell-based experiments. By bridging field studies, molecular biology, and evolutionary theory, we aim to uncover the mechanisms through which early-life environments shape biology across the lifespan and to understand why these effects have evolved.

Relevant publications:
Sadoughi, B.*, Petersen, R. M.*, Patterson, S. K., Slikas, E., Adjangba, C., Ryan, N., ... & Lea, A. J. (2026). Age and early life adversity shape heterogeneity of the epigenome across tissues in macaques. Science, 392(6804), eaea4922.
Petersen, R. M.*, Patterson, S. K.*, Widdig, A., Turcotte, C. M., Antón, S. C., Williams, S. A., ... & Lea, A. J. (2026). Early-life adversity shapes the relationship between growth and reproduction in free-ranging female rhesus macaques. Proceedings of the National Academy of Sciences, 123(19), e2524909123.
Petersen, R.M., Tennyson, R., A/P Tan Boon Huat, T. B. T., Tam, K. L., Watowich, M. M., Solhaimi bin Fadzil, K., ... & Lea, A. J. (2026). Early life environments shape adult cardiometabolic health during rapid lifestyle change. Proceedings of the Royal Society, B. 293 (2069): 20252856
Patterson, S. K.*, Petersen, R. M.*, Brent, L. J., Snyder-Mackler, N., Lea, A. J., & Higham, J. P. (2023). Natural animal populations as model systems for understanding early life adversity effects on aging. Integrative and comparative biology, 63(3), 681-692.

Context-dependent gene regulation

Much of the genetic variation underlying complex traits, disease, and adaptation lies in noncoding regions of the genome, where variants can shape when, where, and how strongly genes are expressed. The effects of this genetic variation are often context dependent, varying with the molecular, ecological, and social environments individuals experience across the life course. Our research investigates how these contexts modify the effects of genetic variation on gene regulation and phenotype. We study context dependence across biological scales, from interactions between DNA sequence and epigenetic variation at regulatory elements to differences in genetic effects across diverse human environments. By integrating genomic, environmental, and health data from natural populations with targeted experimental approaches, we aim to uncover the regulatory mechanisms underlying gene-by-environment interactions and understand how they contribute to variation in complex traits, health, and evolutionary fitness.

Relevant publications:
Petersen, R. M., Vockley, C. M., & Lea, A. J. (2025). Uncovering methylation-dependent genetic effects on regulatory element function in diverse genomes. Genome Research, 35(8), 1781-1793.
Watowich, M.M., Petersen, R.M., Brassington, L., Arner, A.M., Rodenberg, G., Tan Boon Huat, T.B.T., … & Lea, A. J. (2026) Divergent biological consequences of APOE isoforms across industrialized and non-industrialized environments. PLoS Genetics 22(9): e1012285.

Genetic variation and female mate choice

In many primates, sexual dimorphism and male coercion can constrain females’ ability to control which males they mate with. In these contexts, physiological processes within the female reproductive tract that influence which sperm ultimately succeed. This phenomenon, termed cryptic female choice, could provide an important, but largely hidden, mechanism of mate choice. Although evolutionary theory predicts that cryptic female choice may occur in primates, we know surprisingly little about the biological mechanisms that could allow females to influence paternity after mating. Our research investigates these mechanisms by asking how the female reproductive tract responds to mating and whether those responses differ depending on the male’s genetic makeup. In particular, we use transcriptomic approaches to examine changes in gene expression within the vaginal tract, providing a window into how molecular interactions between females and their mates may shape fertilization and reproductive success.

Relevant publications:
Petersen, R. M., Nonnamaker, L. E. M., Anderson, J. A., Bergey, C. M., Roos, C., Melin, A. D., & Higham, J. P. (2026). Evidence for genetically-based sperm discrimination in the vaginal tract of a primate species. Plos Biology, 24(3), e3003699.
Petersen, R. M., Bergey, C. M., Roos, C., & Higham, J. P. (2022). Relationship between genome‐wide and MHC class I and II genetic diversity and complementarity in a nonhuman primate. Ecology and evolution, 12(10), e9346.