DNA methylation signatures of early life adversity are exposure-dependent in wild baboons.

The environment animals face when young can affect how they function throughout life. Long-lasting changes in DNA methylation-a chemical mark deposited on DNA that can affect gene activity-have been hypothesized to contribute to early life effects. But evidence for persistent, early environment-associated differences in DNA methylation is lacking in wild animals. Here, we show that early life adversity in wild baboons predicts DNA methylation levels in adulthood, especially for animals born in low resource environments and drought conditions. We also show that some of the changes we observe in DNA methylation have the capacity to influence gene activity levels. Together, our results support the idea that early experiences can become biologically embedded in the genomes of wild animals.