Telomere length and age in humpback whales (Megaptera novaeangliae)

Telomeres are DNA sequences situated at the end of chromosomes that play a key role in maintaining chromosome integrity and are crucial for normal cell function. In vertebrates, telomeres tend to shorten with age, ultimately reaching a threshold believed to trigger cellular and organismal senescence. The average shortening of telomeres with age and the apparent variability among individuals within a species suggest the potential use of telomeres as an indicator for individual age, fitness and species life-history characteristics. A fast and reliable method to obtain such information from free-ranging animals will have wide applications within marine mammal science and management. Here we report on the relationship between telomere length and age in free-ranging humpback whales (Megaptera novaeangliae). We used quantitative PCR to estimate the rate of telomere shortening in vivo from multiple samples collected from 30 individual humpback whales. We also estimated telomere lengths in additional 18 individuals of known ages. The correlation between telomere length and age was very weak, and highly variable among individuals of similar age. These results are consistent with the life history strategy of this species and suggest that humpback whales may have evolved mechanisms to maintain telomere length, but with varying efficiency among individuals. Moreover, the results indicate that telomere length measured by quantitative PCR is an imprecise determinant of age in humpback whales. We discuss the potential factors responsible for the observed patterns and provide perspectives for applying telomere length estimates in studies of baleen whales