DNA methylation-based age prediction and sex-specific epigenetic aging in a lizard with female-biased longevity

Sex differences in lifespan are widespread across animal taxa, but their causes remain unresolved. Alterations to the epigenome are hypothesized to contribute to vertebrate aging, and DNA methylation-based aging clocks allow for quantitative estimation of biological aging trajectories. Here, we investigate the influence of age, sex, and their interaction on genome-wide DNA methylation patterns in the brown anole (Anolis sagrei), a lizard with pronounced female-biased survival and longevity. We develop a series of age predictor models and find that contrary to our predictions, rates of epigenetic aging were not slower in female lizards. However, methylation states at loci acquiring age-associated changes appear to be more “youthful” in young females, suggesting that female DNA methylomes are preemptively fortified in early life in opposition to the direction of age-related drift. Collectively, our findings provide new insights into epigenetic aging in reptiles and suggest that early-life..., Organism: Anolis sagrei
Tissue: Red blood cells
Genotype: WT
Sampling protocol: Animals were immediately euthanized by decapitation. Blood was collected from the trunk and stored on ice prior to separation of plasma and blood cells by centrifugation. All tissue samples and blood components were snap-frozen in liquid nitrogen.
Husbandry protocol: Animals used in this study were captive-bred descendants of stock originally collected from native A. sagrei populations near Georgetown, Great Exuma, in the Commonwealth of the Bahamas (23º29’N, 75º45’W) and imported under permits from the Bahamas Environment, Science, and Technology Commission, the Bahamas Ministry of Agriculture, and the United States Fish and Wildlife Service. Animals were housed at the University of Virginia and all procedures were approved under UVA ACUC protocol 3896. The exact hatch date of each captive-bred animal was recorded such that age was known with certainty.
Extracted molecule: genomic DNA
Extraction protocol: D..., , # DNA methylation-based age prediction and sex-specific epigenetic aging in a lizard with female-biased longevity

[https://doi.org/10.5061/dryad.3j9kd51sw](https://doi.org/10.5061/dryad.3j9kd51sw)

## Description of the data and file structure

This repository is associated with the publication: Shealy et al. (2025). DNA methylation-based age prediction and sex-specific epigenetic aging in a lizard with female-biased longevity. Science Advances. In Press.

Briefly, in this study, DNA was obtained from *Anolis sagrei* red blood cells from individuals of various age groups and both sexes, and DNA methylation data was generated using a high-throughput sequencing approach.

This repository contains the methylation frequency tables which, along with the coordinates of differentially methylated cytosines in the supplementary material of the manuscript, allows the reproduction of the main findings in the study.

The scripts necessary to process Bismark methylation data into the matrices found...