Data from: Age estimation in a long-lived seabird (Ardenna tenuirostris) using DNA methylation-based biomarkers

Age structure is a fundamental aspect of animal population biology. Age is
strongly related to individual physiological condition, reproductive
potential and mortality rate. Currently, there are no robust molecular
methods for age estimation in birds. Instead, individuals must be ringed
as chicks to establish known-age populations, which is a labour intensive
and expensive process. The estimation of chronological age using DNA
methylation is emerging as a robust approach in mammals including humans,
mice and some non-model species. Here we quantified DNA methylation in
whole blood samples from a total of 71 known-age Short-tailed shearwaters
(Ardenna tenuirostris) using digital restriction enzyme analysis of
methylation (DREAM). The DREAM method measures DNA methylation levels at
thousands of CpG dinucleotides throughout the genome. We identified seven
CpG sites with DNA methylation levels that correlated with age. A model
based on these relationships estimated age with a mean difference of 2.8
years to known age, based on validation estimates from models created by
repeated sampling of training and validation data subsets. Longitudinal
observation of individuals re-sampled over 1 or 2 years generally showed
an increase in estimated age (6/7 cases). For the first time, we have
shown that epigenetic changes with age can be detected in a wild bird.
This approach should be of broad interest to researchers studying age
biomarkers in non-model species and will allow identification of markers
that can be assessed using targeted techniques for accurate age estimation
in large population studies.