Telomere dynamics in a lizard with morph-specific reproductive investment and self-maintenance.

Nicky Rollings,Mathieu Giraudeau,Mark Wilson,Mats Olsson,Christopher R Friesen,Joanna Sudyka,Camilla Whittington

doi:10.1002/ece3.2712

Abstract

Telomeres in human fibroblasts shorten progressively during in vitro culturing and trigger replicative senescence. Furthermore, shortened telomeres can be used as biomarkers of disease. These observations have led to the suggestion that telomere dynamics may also be associated with viability and selection for life history variation in non‐human taxa. Model systems to examine this suggestion would particularly benefit from the coexistence of multiple phenotypes within the same species with different life history trade‐offs, since those could be compared in terms of telomere characteristics. This scenario also provokes the classic question of why one morph does not have marginally higher fitness and replaces the others. One explanation is that different morphs have different reproductive tactics with equal relative fitness. In Australian painted dragons (Ctenophorus pictus), males differ in head color, the presence or absence of a gular bib, and reproductive expenditure. Red males out‐compete yellow males in dominance contests, while yellow males copulate quickly and have higher success in sperm competition than red males. Males with bibs better defend partners against rival matings, at the cost of loss of body condition. We show that yellow‐headed and bib‐less males have longer telomeres than red, blue and bibbed males, suggesting that telomere length is positively associated with higher investment into self‐maintenance and less reproductive expenditure.

Highlights

Telomeres are tandem nucleotide repeats (TTAGGG in most metazoans, Gomes, Shay, & Wright, 2010) found at the ends of chromosomes (Blackburn & Gall, 1978; Hug & Lingner, 2006) that can lengthen or shorten during an organism’s life in response to stress and ageing (Harley, Futcher, & Greider, 1990; Liu, 2014)
Yellow males have larger testes and four times higher reproductive success in sperm competition trials than red males, despite much shorter copulations (Olsson, Schwartz, Uller, & Healey, 2009). This suggests that these two morphs exhibit alternative reproductive tactics that likely result from fundamental differences in trade-offs of resources between testes, testosterone-driven aggression, and longevity
This study provides the first evidence that individuals with different reproductive and life history tactics of the same species have different telomere dynamics

Summary

| INTRODUCTION

Telomeres are tandem nucleotide repeats (TTAGGG in most metazoans, Gomes, Shay, & Wright, 2010) found at the ends of chromosomes (Blackburn & Gall, 1978; Hug & Lingner, 2006) that can lengthen or shorten during an organism’s life in response to stress and ageing (Harley, Futcher, & Greider, 1990; Liu, 2014). Yellow males have larger testes and four times higher reproductive success in sperm competition trials than red males, despite much shorter copulations (Olsson, Schwartz, Uller, & Healey, 2009) This suggests that these two morphs exhibit alternative reproductive tactics that likely result from fundamental differences in trade-offs of resources between testes, testosterone-driven aggression, and longevity. In order to better understand the underlying role of telomeres in the mediation of life history biology, we used a two-pronged approach Given their differences in reproductive expenditure, somatic maintenance, growth, ageing, stress, and elevated testosterone levels, telomere dynamics are predicted to vary among morphs. This manipulation had no effect and is reported in Appendix I to minimize the interruption of the text

| METHODS

Findings

| DISCUSSION