As the average lifespan of the world population continues to increase, deciphering the biological underpinnings of natural variation in aging and lifespan are becoming critical to managing aging-related diseases. While many genes regulating lifespan have been identified, the epigenetic factors regulating lifespan and aging are largely unexplored. Here, we use five Drosophila melanogaster lines selected for postponed reproductive senescence for over 170 generations (O lines) and five lines from the same base population without selection maintained (B lines) to assess differential epigenetic modifications. The O lines live approximately twice as long as the B lines. We are using ATAC-seq to determine changes in open chromatin from a variety of tissues in both sexes of the O and B lines at several developmental and adult time points; and ChIP-seq to target histone modifications at different ages in these divergent lines. In conjunction with previous genomic, transcriptomic, metabolomic, and phenotypic data, we will derive putative causal relationships between epigenetic modifications and natural variation in lifespan.