A putative telomerase activator has tissue‐specific effects on telomere length in a developing songbird

Abstract

There is good evidence that telomeres predict variation in health and longevity, yet it is unclear whether these patterns are causally derived from telomeres per se, in part because relatively little research directly manipulates telomere length during early life, when telomere shortening is most dynamic. Here, we test how the telomerase activator TA‐65 (i.e. cycloastrogenol) affects telomere length in five tissues during the peak of growth in the wild tree swallow Tachycineta bicolor. Following eight days of oral TA‐65 administration, chicks experienced telomere lengthening in the blood and accelerated feather growth, but no changes to mass over time. TA‐65 did not affect telomere length in the brain or spleen and led to shorter telomeres in the liver and adrenals. This whole‐organism experimental manipulation of telomere dynamics therefore reveals limitations to telomere protection and biological senescence. In doing so, this work advances our understanding of early‐life telomere dynamics and their potential role in generating future variation in health and lifespan.