Meeting Abstract
Understanding the mechanisms that contribute to variation in longevity is critical to evolutionary ecology and biomedicine. Telomeres, protective caps at the end of eukaryotic chromosomes that enhance genome stability, may be one mechanism that is important. In the absence of restoration, telomeres shorten during cell division and in response to stress and limit cellular lifespan. Once telomeres reach a critically short length, cells stop dividing and begin to senesce. Recent evidence shows individuals with longer telomeres during early life live longer. However, whether telomeres are causally related to longevity, or simply a biomarker, or both is currently unknown and manipulation of telomere length will be essential to disentangle these possibilities. Telomeres can be extended by telomerase, an enzyme that is expressed during embryonic development and down-regulated in most somatic tissues soon after birth or hatching. Previous research suggests that TA-65, a plant extract from the Astragalus membranaceus root, lengthens telomeres by increasing telomerase expression. To investigate the causal role of telomeres in early life, we experimentally manipulated TA-65 in growing free-living house sparrows (Passer domesticus) and examined the effect on telomere length and loss. Nests were randomly assigned to either a control or experimental treatment group. Between days 2-10 post-hatch, experimental nestlings received daily oral doses of TA-65 in sterile water and control nestlings received daily oral doses of sterile water. Blood samples were collected from all of the nestlings on days 2 and 10 to measure telomere length and loss Growth measurements were collected every 3 days. We predicted that experimental nestlings would experience less telomere loss and have longer telomeres than controls.
