Individual telomere dynamics and their links to life history in a viviparous lizard

Abstract

Emerging patterns suggest telomere dynamics and life history are fundamentally linked in endotherms through life-history traits that mediate the processes underlying telomere attrition. Unlike endotherms, ectotherms maintain the ability to lengthen somatic telomeres throughout life and the link between life-history strategies and ectotherm telomere dynamics is unknown. In a well-characterized model system (Niveoscincus ocellatus), we used long-term longitudinal data to study telomere dynamics across climatically divergent populations. We found longer telomeres in individuals from the cool highlands than those from the warm lowlands at birth and as adults. The key determinant of adult telomere length across populations was telomere length at birth, with population-specific effects of age and growth on adult telomere length. The reproductive effort had no proximate effect on telomere length in either population. Maternal factors influenced telomere length at birth in the warm lowlands but not the cool highlands. Our results demonstrate that life-history traits can have pervasive and context-dependent effects on telomere dynamics in ectotherms both within and between populations. We argue that these telomere dynamics may reflect the populations' different life histories, with the slow-growing cool highland population investing more into telomere lengthening compared to the earlier-maturing warm lowland population.

Keywords: ageing; climate; life history; reproductive senescence; reptile; telomere.

Figure 1.

Predicted relationships between environment, reproduction, age, growth and telomere length in Niveoscincus ocellatus.

Figure 2.

Experimental design: number of juvenile and adult Niveoscincus ocellatus samples from each site (warm lowland population and cool highland population).

Figure 3.

Telomere length (T/S ratio) is longer in the cool highland population than the warm lowland population in both (a) juvenile and (b) adult Niveoscincus ocellatus. Means and confidence intervals presented. (Online version in colour.)

Figure 4.

Telomere length (T/S ratio) of juvenile Niveoscincus ocellatus with (a) maternal telomere length and (b) maternal age. Circles, cool highland population; triangles and trend line, warm lowland population. (Online version in colour.)

Figure 5.

Telomere length (T/S ratio) of juveniles is strongly correlated with telomere length of individuals as adults in both the cool highland population and the warm lowland population of Niveoscincus ocellatus. Circles and solid line, cool highland population; triangles and dashed line, warm lowland population. Dotted line indicates 1 : 1. (Online version in colour.)