Epigenetic approaches to aging individuals in wildlife populations using telomere length

<p dir="ltr">Wildlife populations provide numerous ecosystem services, such as their role in pollination, seed dispersal, nutrient cycling, and pest control. They also serve as a source for human food and materials, and are often of cultural and spiritual significance. In order to maintain wild populations, it is imperative to understand their demography. Capturing the age structure of populations is a critical aspect in obtaining a deeper understanding of population dynamics for developing management strategies. Age in various wildlife species has long been assessed with physical characteristics, such as body mass or size, coloration, and bone growth. Since the 1940s, tooth wear and replacement has been used for individual aging but it is subjective, invasive, and limited to game animals that are harvested. Cementum annuli analysis can be applied across mammalian taxa, but the technique is costly and remains subjective and invasive. Because the use of DNA profiles has revolutionized many aspects of wildlife biology (e.g., the noninvasive evaluation of hair, shed feathers, or scat DNA can determine sex, individual identity, and parentage/relatedness), we explored the use of epigenetic components of the genome to assess individual age using telomeres. Terminal telomeres—short nucleotide sequences at chromosome ends—have been linked to chronological age at the population level, yet there is little research validating this method in wildlife species. Using ultra-conserved DNA elements and quantitative polymerase chain reaction (qPCR), this study aimed to evaluate the effectiveness of using telomere length as an indicator of chronological age in coyotes (<i>Canis latrans</i>) and white-tailed deer (<i>Odocoileus virginianus</i>). Our findings reveal that while telomere length correlates with age in these species, it is not a reliable predictor. Telomere length and age were negatively correlated for most samples, but antler samples exhibited a positive correlation potentially influenced by effective population size (Ne). This highlights the complexity of using telomere length for age estimation in wildlife populations and underscores the need for further research into alternative methods that are accurate, non-invasive, and applicable across diverse species.</p>