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- Olsson, Mats, 1960, et al.
(författare)
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Proximate determinants of telomere length in sand lizards (Lacerta agilis)
- 2010
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 6:5, s. 651-653
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Olsson, Mats, 1960, et al.
(författare)
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Sex differences in sand lizard telomere inheritance: paternal epigenetic effects increases telomere heritability and offspring survival
- 2011
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Ingår i: PLoS One. - : Public Library of Science (PLoS). - 1932-6203. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: To date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve. Methodology/Principal findings: Here, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g., males vs females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations. Conclusions/Significance: TL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival.
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| 3. |
- Olsson, Mats, 1960, et al.
(författare)
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Sexual differences in telomere selection in the wild
- 2011
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Ingår i: Molecular Ecology. ; 20, s. 2085-2099
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Tidskriftsartikel (refereegranskat)abstract
- Telomere length is restored primarily through the action of the reverse transcriptase telomerase, which may contribute to a prolonged lifespan in some but not all species and may result in longer telomeres in one sex than the other. To what extent this is an effect of proximate mechanisms (e.g., higher stress in males, higher estradiol/estrogen levels in females), or is an evolved adaptation (stronger selection for telomere length in one sex), usually remains unknown. Sand lizard (Lacerta agilis) females have longer telomeres than males and better maintain telomere length through life than males do. We also show that telomere length more strongly contributes to life span and lifetime reproductive success in females than males and that telomere length is under sexually diversifying selection in the wild. Finally, we performed a selection analysis with number of recruited offspring into the adult population as a response variable with telomere length, life span and body size as predictor variables. This showed significant differences in selection pressures between the sexes with strong ongoing selection in females, with these three predictors explaining 63% of the variation in recruitment. Thus, the sexually dimorphic telomere dynamics with longer telomeres in females is a result of past and ongoing selection in sand lizards. Finally, we compared the results from our selection analyses based on Telometric-derived data to the results based on data generated by the software ImageJ. ImageJ resulted in shorter average telomere length, but this difference had virtually no qualitative effect on the patterns of ongoing selection.
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