Meeting Abstract

P1.41  Friday, Jan. 4  Telomeres: ghosts of stressors past and harbingers of things to come? VLECK., D*; VLECK, C ; FOOTE, C; WINKLER, D; Iowa State Univ, Ames; Iowa State Univ, Ames; Iowa State Univ, Ames; Cornell Univ. Ithaca NY dvleck@iastate.edu

Telomeres shorten with cell replication and oxidative stress. Shorter telomeres are correlated with reduced long-term survival. We produced a long-term metabolic stress in breeding tree swallows by attaching a 1-g backpack that the birds carried for a year. Doubly-labeled water data suggests this handicap (~5% of bird’s mass) increased metabolic rate ~6%. Over the course of the year, mean telomere length measured by telomere restriction fragment analysis of nucleated erythrocytes decreased by 0.4 kb (95%CI±0.2) in metabolically stressed birds, significantly more (p=0.002) than occurred in control birds (mean loss 0.08 kb, 95%CI±0.1). Plasma innate immunity, total antioxidant defense and H₂O₂ level and comet analysis of cellular DNA damage did not differ between groups. Increased telomere shortening suggests that metabolic stress increased oxidative damage. In the first year, we found no difference in return rate to breeding sites (an index of survival) in backpack-carrying and control birds, but the odds ratio of return after a second year was strongly influenced by both the bird’s initial telomere length (longer telomeres increased the odds of return) and its rate of shortening (greater shortening decreased odds of return). In our sample, sex, age, breeding site and year did not affect return odds. These data support the idea that telomere length and its rate of shortening reflect past stressors and predict future survival. Telomeres, which can be repeatedly measured in the same individual, may provide an integrative measure of individual quality and individual history, and provide a tool for predicting future ramifications of stress associated with experimental procedures or environmental variation.