Joseph M. Northrup

Abstract White-tailed deer (Odocoileus virginianus) are an ecologically and economically important species in North America. Their antlers, one of their most recognizable features, are used for dominance displays, mate attraction, and defense, with size and morphology being key determinants of success. Antler characteristics are influenced by a combination of genetic and environmental factors, including habitat quality and resource availability.

1 INTRODUCTION DNA methylation (DNAm) is an epigenetic modification primarily associated with the regulation of gene expression (Gallego-Bartolomé, 2020; Jung & Pfeifer, 2015). The process involves the transfer of a methyl group to or from a cytosine base (Jung & Pfeifer, 2015; Lyko, 2018; Moore et al., 2013). In mammalian genomes, this occurs primarily at cytosines that precede a guanine, also referred to as CpG sites (Moore et al., 2013).

Abstract The development of epigenetic clocks, or the DNA methylation-based inference of age, is an emerging tool for ageing in free ranging populations. In this study, we developed epigenetic clocks for three species of large mammals that are the focus of extensive management throughout their range: white-tailed deer, black bear, and mountain goat. We quantified differential DNA methylation patterns at over 30,000 cytosine-guanine sites (CpGs) from tissue samples (N=141) of all three species.