How does early‐life adversity shape telomere dynamics during adulthood? Problems and paradigms

Abstract

Although early-life adversity has been associated with negative consequences during adulthood, growing evidence shows that such adversity can also lead to subsequent stress resilience and positive fitness outcomes. Telomere dynamics are relevant in this context because of the link with developmental conditions and longevity. However, few studies have assessed whether the effects of early-life adversity on developmental telomere dynamics may relate to adult telomere dynamics. We propose that the potential links between early-life adversity and adult telomere dynamics could be driven by developmental constraints (the Constraint hypothesis), by the nature/severity of developmental adversity (the Resilience hypothesis), or by developmental-mediated changes in individual life-history strategies (the Pace of Life hypothesis). We discuss these non-mutually exclusive hypotheses, explore future research directions, and propose specific studies to test these hypotheses. Our article aims to expand our understanding of the evolutionary role of developmental conditions on adult telomere dynamics, stress resilience and ageing.

Longitudinal telomere dynamics within natural lifespans of a wild bird

“…2). This suggests that the negative effects of growth [44], environmental stressors [46] and inbreeding [80] on early-life TL previously described in these populations may have lasting effects on TL later in life [15,78]. Recent studies have found a positive genetic correlation close to 1 between TL measurements within individuals, suggesting that the same genes are involved in controlling TL at different ages [28,38,43].…”

“…We found a considerable effect of hatch year, which explained 37% of the variance in ∆TL (vs. 4% in [43]). This may re ect environmental variation experienced by different cohorts in early-life such as weather conditions and competition [39,46] and suggests that there are persistent impacts of the early-life environment on TL shortening later in life [15].…”

“…For instance, telomeres may shorten in response to stress associated with reproduction [10,11], growth [12], or harsh abiotic conditions in wild populations [13]. Consequently, TL may be a causal mediator of effects of growth and early-life conditions on later-life senescence [14,15], and TL predict tness components such as survival and reproductive success [16,17].…”

“…However, there are also studies suggesting that telomere shortening rates are greater in individuals with initially longer telomeres [23,[29][30][31] perhaps because longer telomeres present a larger target for oxidative damage [32][33][34][35]. Such an effect may shape the observed associations between early-life TL, stress exposure and tness [15,36,37].…”

Conceptual and analytical approaches for modeling the developmental origins of inequality

“…As conceptualized above, the DC and PAR hypotheses are not mutually exclusive, as many others have noted [19, 20, 11, 21]. Adult outcomes can simultaneously be determined by the quality of the developmental environmental and how well organisms predict some feature of adulthood (Figure 1c) [18, 22].…”