Proximate determinants of telomere length in sand lizards ( Lacerta agilis )

Abstract

Telomeres are repeat sequences of non-coding DNA that cap the ends of chromosomes and contribute to their stability and the genomic integrity of cells. In evolutionary ecology, the main research target regarding these genomic structures has been their role in ageing and as a potential index of age. However, research on humans shows that a number of traits contribute to among-individual differences in telomere length, in particular traits enhancing cell division and genetic erosion, such as levels of free radicals and stress. In lizards, tail loss owing to predation attempts results in a stress-induced shift to a more cryptic lifestyle. In sand lizard (Lacerta agilis) males, telomere length was compromised by tail regrowth in a body size-related manner, so that small males, which already exhibit more cryptic mating tactics, were less affected than larger males. Tail regrowth just fell short of having a significant relationship with telomere length in females, and so did age in males. In females, there was a significant positive relationship between age and telomere length. We conclude that the proximate effect of compromised antipredation and its associated stress seems to have a more pronounced effect in males than in females and that age-associated telomere dynamics differ between the sexes.

Age, Sex, and Telomere Dynamics in a Long-Lived Seabird with Male-Biased Parental Care

“…TL is measured in a variety of ways in the ecological literature. The most common methods are the Southern blot-derived telomere restriction fragment (TRF) assay [9–11], smaller windows of the TRF smear [12], and quantitative PCR [8,13,14]. Here we compare the effects of age, sex, and colony on telomere length as estimated by each of those methods.…”

Sex Differences in Sand Lizard Telomere Inheritance: Paternal Epigenetic Effects Increases Telomere Heritability and Offspring Survival

“…We show elsewhere that in sand lizards ( Lacerta agilis ), there are sex-specific effects relating to telomere length (TL), such as stress-tolerance from predation [4] and positive selection in the wild relating to increased lifespan and lifetime reproductive success (stronger in females; 4; oral report at the Swedish Telomere and Telomerase Network Annual Meeting, Sven Lovén Centre, May 2010; Olsson et al submitted). However, the genetic architecture and epigenetic aspects of the underlying processes determining telomere length have not been addressed, which makes it difficult to assess the evolutionary implications of selection patterns.…”

Sex differences in telomeres and lifespan

“…The Maier et al (2008) study, discussed earlier, showed that human cell replicative capacity is dependent on height when the donor is male, but not when female. Moreover, large male dunlins (Calidris alpine) and sand lizards (Lacerta agilis) have shorter telomeres than small males, but size does not affect female telomere length, despite them being the larger sex (Pauliny et al, 2006;Olsson et al, 2010;respectively). Nevertheless, most species with no sex differences in telomere length or shortening do still show an age-related decline in telomere length (Table 1), which we might not expect if telomeres were fully maintained by telomerase.…”