Is Telomere Length Optimized in Hatchling Sand Lizards?

Area of Science:

• Evolutionary Biology
• Genetics
• Herpetology

Background:

• Telomeres, protective DNA-protein structures at chromosome ends, are crucial for cellular integrity.
• Natural selection may favor optimal telomere length for enhanced individual viability and reproductive success.
• Limited data exist for ectothermic vertebrates regarding telomere length dynamics and fitness correlations.

Purpose of the Study:

• To investigate the relationship between telomere length and fitness (lifespan, reproductive success, offspring recruitment) in a natural population of sand lizards (Lacerta agilis).
• To examine facultative telomere length adjustments in ectotherms and their associated costs.

Main Methods:

• A decade-long study involving over 1700 hatchling sand lizards and their 500 parents.
• Measurement of 2736 telomeres across individuals.
• Tracking of lifespan, lifetime reproductive success, and offspring recruitment rates.

Main Results:

• Hatchlings with average-length telomeres exhibited the highest lifespan, lifetime reproductive success, and offspring recruitment.
• Lizards with shorter-than-average telomeres elongated them to the population average by sexual maturity.
• Compensatory telomere elongation was associated with reduced body condition in juvenile lizards.

Conclusions:

• Telomere length is under natural selection in sand lizards, with intermediate lengths conferring fitness advantages.
• Facultative telomere elongation can occur but may impose a physiological cost, impacting body condition.
• Findings contribute to understanding telomere dynamics and their evolutionary implications in free-ranging ectotherms.