Utility of telomere length measurements for age determination of humpback whales

Morten Tange Olsen,Jooke Robbins,Per J Palsbøll,Martine Bérubé,Mary Beth Rew

doi:10.7557/3.3194

Abstract

This study examines the applicability of telomere length measurements by quantitative PCR as a tool for minimally invasive age determination of free-ranging cetaceans. We analysed telomere length in skin samples from 28 North Atlantic humpback whales (Megaptera novaeangliae), ranging from 0 to 26 years of age. The results suggested a significant correlation between telomere length and age in humpback whales. However, telomere length was highly variable among individuals of similar age, suggesting that telomere length measured by quantitative PCR is an imprecise determinant of age in humpback whales. The observed variation in individual telomere length was found to be a function of both experimental and biological variability, with the latter perhaps reflecting patterns of inheritance, resource allocation trade-offs, and stochasticity of the marine environment.

Highlights

The most commonly applied approaches for age determination of cetaceans are based on counting of growth layer groups (GLGs) in hard structures such as dentine, bone, baleen plates and ear plugs (Chittleborough 1965; Laws 1952, and this volume), as well as eye-nucleus aspartic acid racemisation (Garde et al 2007; George et al 1999; Nielsen et al 2013; Olsen & Sunde 2002)
We applied the qPCR approach to telomere length estimation (Cawthon 2002; Cawthon 2009) to investigate the prospect of using telomere length as a proxy for chronological age in a cetacean species in which individuals have been studied for nearly four decades
For the described sampling scheme and experimental techniques, telomere lengths in humpback whales only weakly correlated with age and were highly variable among individual whales (Fig. 1)

Summary

Introduction

The most commonly applied approaches for age determination of cetaceans are based on counting of growth layer groups (GLGs) in hard structures such as dentine, bone, baleen plates and ear plugs (Chittleborough 1965; Laws 1952, and this volume), as well as eye-nucleus aspartic acid racemisation (Garde et al 2007; George et al 1999; Nielsen et al 2013; Olsen & Sunde 2002). For free-ranging cetaceans, photo-ID records can be used to track identified individuals from their year of birth (Hammond et al 1990; Katona & Whitehead 1981), but require substantial efforts in time and. Olsen MT, Robbins J, Bérubé M, Rew MB and Palsbøll PJ (2014) Utility of telomere length measurements for age determination of humpback whales. The age-estimates of both methods were associated with 95% confidence intervals of up to 8-10 years, suggesting that alternative methods that are more accurate may still be of interest

Methods

Results

Conclusion