Telomere length and age in humpback whales (<i>Megaptera novaeangliae</i>)

Telomeres are DNA sequences situated at the end of chromosomes that playa key role in maintaining chromosome integrity and are crucial for normalcell function. In vertebrates, telomeres tend to shorten with age, ultimatelyreaching a threshold believed to trigger cellular and organismal senescence.The average shortening of telomeres with age and the apparent variabilityamong individuals within a species suggest the potential use of telomeres asan indicator for individual age, fitness and species life-history characteristics.A fast and reliable method to obtain such information from free-ranginganimals will have wide applications within marine mammal science andmanagement. Here we report on the relationship between telomere length andage in free-ranging humpback whales (Megaptera novaeangliae). We usedquantitative PCR to estimate the rate of telomere shortening in vivo frommultiple samples collected from 30 individual humpback whales. We alsoestimated telomere lengths in additional 18 individuals of known ages. Thecorrelation between telomere length and age was very weak, and highlyvariable among individuals of similar age. These results are consistent withthe life history strategy of this species and suggest that humpback whalesmay have evolved mechanisms to maintain telomere length, but with varyingefficiency among individuals. Moreover, the results indicate that telomerelength measured by quantitative PCR is an imprecise determinant of age inhumpback whales. We discuss the potential factors responsible for theobserved patterns and provide perspectives for applying telomere lengthestimates in studies of baleen whales