Telomere length positively correlates with pace-of-life in a sex- and
cohort-specific way and elongates with age in a wild mammal
Abstract
Understanding ageing and the diversity of life histories is a
cornerstone in biology. Telomeres, the protecting caps of chromosomes,
are thought to be involved in ageing, cancer risks and to modulate
life-history strategies. They shorten with cell division and age in
somatic tissues of most species, possibly limiting lifespan. The
resource allocation trade-off hypothesis predicts that short telomeres
have thus co-evolved with early reproduction, proactive behaviour and
reduced lifespan: a fast Pace-of-Life Syndrome (POLS). Conversely, since
short telomeres may also reduce the risks of cancer, the anti-cancer
hypothesis advances that they should be associated with slow POLS.
Conclusion on which hypothesis best supports the role of telomeres as
mediators of life-history strategies is hampered by a lack of study on
wild short-lived vertebrates, apart from birds. Using seven years of
data on wild Eastern chipmunks Tamias striatus, we highlighted that
telomeres elongate with age and do not limit lifespan in this species.
Furthermore, short telomeres correlated with a slow POLS in a
sex-specific way. Females with short telomeres had a delayed age at
first breeding and a lower fecundity rate than females with long
telomeres, whereas those differences were not recorded in males. Our
findings support most predictions adapted from the anti-cancer
hypothesis, but none of those made under the resource allocation
trade-off hypothesis. Results are in line with an increasing body of
evidence suggesting that other evolutionary forces than resource
allocation trade-offs shape the diversity of telomere length in adult
somatic cells and the relationships between telomeres and
life-histories.