Data from: Proportion methylation at a set of CpGs from 4 amplicons

The age structure of populations, or the ageing rate of individuals,
impacts aspects of animal ecology, epidemiology and conservation. Yet for
many wild organisms, age is an inaccessible trait. In many cases measuring
age or ageing rates in the wild requires molecular biomarkers of age.
Epigenetic clocks based on DNA methylation have been shown to accurately
estimate the age of humans and laboratory mice, but they also show
variable ticking rates that are associated with mortality risk above and
beyond that predicted by chronological age. Thus, epigenetic clocks are
proving to be useful markers of both chronological and biological age, and
they are beginning to be applied to wild mammals and birds. We have
acquired strong evidence that an accurate clock will be possible for the
wood mouse Apodemus sylvaticus by adapting epigenetic information from the
laboratory mouse. Apodemus sylvaticus is a well-studied field system that
is amenable to experimental perturbations and longitudinal sampling of
individuals across their lives, and these features of the wood mouse offer
opportunities to disentangle causal relationships between ageing rates and
environmental stress. Our wood mouse epigenetic clock is PCR-based, and so
requires tiny amounts of tissue and non-destructive sampling. We
quantified methylation using Oxford Nanopore sequencing technology and
present a new bioinformatics pipeline for data analysis. We thus describe
a new and generalizable system that should enable ecologists and other
field biologists to go from tiny tissue samples to an epigenetic clock for
their study animal.