Telomere attrition with age in a wild amphibian population

Abstract

Telomere shortening with age has been documented in many organisms, but few studies have reported telomere length measurements in amphibians, and no information is available for growth after metamorphosis, nor in wild populations. We provide both cross-sectional and longitudinal evidence of net telomere attrition with age in a wild amphibian population of natterjack toads (Epidalea calamita). Based on age-estimation by skeletochronology and qPCR telomere length measurements in the framework of an individual-based monitoring programme, we confirmed telomere attrition in recaptured males. Our results support that toads experience telomere attrition throughout their ontogeny, and that most attrition occurs during the first 1-2 years. We did not find associations between telomere length and inbreeding or body condition. Our results on telomere length dynamics under natural conditions confirm telomere shortening with age in amphibians and provide quantification of wide telomere length variation within and among age-classes in a wild breeding population.

Keywords: Epidalea calamita; growth; natterjack toad; senescence; skeletochronology; telomere length.

Figure 1.

(a) Growth functions and simple linear regression models for TL versus (b) age, (c) body condition and (d) inbreeding in males (black dots, solid lines) and females (white dots, dashed lines). The p-value is indicated for the single significant TL model.

Figure 2.

(a) TL measured at the dates of first (black dots) and second capture (grey dots). (b) Observed TL attrition in the same individuals as in (a): 32 males (dark dots) and one female (white dot). The horizontal line delimits telomere shortening (positive attrition) versus elongation (negative attrition). Linear regression models for telomere attrition versus (c) initial TL, (d) age and (e) body condition in 2015 and (f) inbreeding. The p-value is indicated for the single significant TL attrition model.