Telomere dynamics in the first year of life, but not later in life,
predict lifespan in a wild bird
Abstract
Telomeres are protective, nucleoprotein structures at the end of
chromosomes that have been associated with lifespan across taxa.
However, the extent to which these associations can be attributed to
absolute length versus the rate of telomere shortening prior to sampling
remains unresolved. In a longitudinal study, we examined the
relationship between lifespan, telomere length and the rate of telomere
shortening in wild, purple-crowned fairy-wrens (Malurus coronatus
coronatus). To this end, we measured telomere length using qPCR in the
blood of 59 individuals sampled as nestling and 4-14 months thereafter,
and in 150 individuals sampled on average three times across adulthood.
We applied within-subject centering analyses to simultaneously test for
associations between lifespan and average telomere length and telomere
shortening. We reveal that the rate of telomere shortening in the first
year of life predicted lifespan, with individuals with faster shortening
rates living less long. We also report a trend for an effect of telomere
length in the first year of life on lifespan, independent of telomere
shortening. In contrast, in adulthood neither telomere shortening, nor
telomere length predicted lifespan, despite a considerably larger data
set. Our results suggest that telomere length measured very early in
life (during development) and longitudinal assessments of telomere
shortening during the first year of life constitute more useful
biomarkers of total life expectancy than either telomere length measured
after development, or telomere shortening later in adulthood.