AUTHOR=Robeck Todd R. , Fei Zhe , Haghani Amin , Zoller Joseph A. , Li Caesar Z. , Steinman Karen J. , Dirocco Stacy , Staggs Lydia , Schmitt Todd , Osborn Steve , Montano Gisele , Rodriguez Magdalena , Horvath Steve 

TITLE=Multi-Tissue Methylation Clocks for Age and Sex Estimation in the Common Bottlenose Dolphin

JOURNAL=Frontiers in Marine Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.713373

DOI=10.3389/fmars.2021.713373

ISSN=2296-7745

ABSTRACT=<p>Accurate identification of individual ages within wild bottlenose dolphins (<italic>Tursiops truncatus</italic>) is critical for determining population health and the development of population management strategies. As such, we analyzed DNA methylation (DNAm) patterns by applying a custom methylation array (HorvathMammalMethyl40) to both blood (<italic>n</italic> = 140) and skin samples (<italic>n</italic> = 87) from known age or approximate age (0–57 years) bottlenose dolphins. We present three bottlenose dolphin specific age estimation clocks using combined blood and skin [48 CpGs, <italic>R</italic> = 0.93, median absolute error (MAE) = 2.13 years], blood only (64 CpGs, R = 0.97, error = 1.46 years) and skin only (39 CpGs, <italic>R</italic> = 0.95, error = 2.53). We characterized individual cytosines that correlate with sex and age in dolphins and developed a sex estimator based on 71 CpGs that predicts the sex of any odontocete species with 99.5% accuracy. The presented epigenetic clocks are expected to be useful for conservation efforts and for determining if anthropogenic events affect aging rates in wild populations.</p>