Telomere length and rate of change, as they relate to body size and longevity

Telomeres, the terminal repetitive DNA sequences at the ends of linear
chromosomes, have strong associations with longevity in some major taxa.
Longevity has been linked to rate of decline in telomere length in birds
and mammals, and absolute telomere length seems to be associated with body
mass in mammals. Using a phylogenetic comparative method and 30 species of
birds, we examined longevity (reflected by maximum lifespan), absolute
telomere length, the rate of change in telomere length (TROC), and body
mass (often strongly associated with longevity) to ascertain their degree
of association. We divided lifespan into two life-history components, one
reflected by body size (measured as body mass), and a component that was
statistically independent of body mass. While both lifespan and body mass
were strongly associated with a family tree of the species (viz., the
phylogeny of the species), telomere measures were not. Telomere length was
not significantly associated with longevity or body mass, or our measure
of mass-independent lifespan. TROC, however, was strongly associated with
mass-independent lifespan, but only to a much lesser degree at best with
body mass-predicted lifespan. Our results supported an association of TROC
and longevity, in particular longevity that was independent of body size
and part of the pace-of-life syndrome of life histories.