Life Expectancy Highly Correlated with Telomere Length and Dynamics

Studying a bird model in the wild, scientists have for the first time found telomere length and dynamics to be highly predictive of “biological” age and life expectancy for individuals in a given population.

Variation in the length and rate of loss of the protective telomere chromosome caps are known to be major factors linked to cellular lifespan, however, little is known about the extent to which telomere length and dynamics predict organismal lifespan in nature. The 20-year research project, now published November 21, 2012, in the journal Molecular Ecology, is the first of its kind to measure telomeres across the entire lifespan of individuals in a wild population. The model population was a set of 320 Seychelles Warblers, formally Acrocephalus sechellensis, with essentially no predators on the small, well-isolated Cousin Island. The researchers studied life-long adult telomere dynamics (1-17 years) and their relationship to mortality under natural conditions in a sample subset of 204 individuals. Blood samples were collected twice per year and telomere length analyzed. The results showed that individuals differ radically in how quickly their telomeres shorten with age, having shorter telomeres at any age is associated with an increased risk of death, and that telomere length is a better indicator of future life-expectancy than chronological age and may therefore act as an indicator of biological age.



“The Seychelles Warbler is [also ideal in that] we can follow individuals throughout their lives, right through to old age,” said lead scientist Dr. David S. Richardson of the University of East Anglia (Norwich, UK). “It would be virtually impossible to do such a study in humans. For one thing, it would take a very long time to study a human lifespan. Also in humans we would normally, quite rightly, intervene in cases of disease, so it wouldn’t be a natural study,” he added.

About the results, Dr. Richardson further explained: “We investigated whether, at any given age, their telomere lengths could predict imminent death. We found that short and rapidly shortening telomeres were a good indication that the bird would die within a year. We also found that individuals with longer telomeres had longer life spans overall. [...] While telomeres do shorten with chronological age, the rate at which this happens differs between individuals of the same age [largely as they] experience different amounts of biological stress due to the challenges and exertions they face in life. We found that telomeres are linked to body condition and reflect the history of oxidative stress that has occurred within an individual’s lifetime. The healthier you are, or have been, the better telomeres you have. But it’s hard to know whether this is a consequence of being healthy or a cause.”

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University of East Anglia