Age estimation based on blood DNA methylation levels in brown bears

Age is an essential trait for understanding the ecology and management of wildlife. A conventional method of estimating age in wild animals is counting annuli formed in the cementum of teeth. This method has been used in bears despite some disadvantages, such as high invasiveness and the requirement...

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Bibliographic Details
Published in:Molecular ecology resources 2023-08, Vol.23 (6), p.1211-1225
Main Authors: Nakamura, Shiori, Yamazaki, Jumpei, Matsumoto, Naoya, Inoue‐Murayama, Miho, Qi, Huiyuan, Yamanaka, Masami, Nakanishi, Masanao, Yanagawa, Yojiro, Sashika, Mariko, Tsubota, Toshio, Ito, Hideyuki, Shimozuru, Michito
Format: Article
Language:English
Subjects:
Age
Age determination
age estimation
aging
Aging - genetics
Animals
Bears
Bisulfite
Blood
brown bear
Captivity
Cementum
Chronology
CpG Islands
Cytosine
Deoxyribonucleic acid
DNA
DNA Methylation
Ecological research
Epigenesis, Genetic
epigenetic clock
Epigenetics
Estimation
Genes
Invasiveness
Phenotype
Teeth
Ursidae - genetics
Wild animals
Wildlife management
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Summary:Age is an essential trait for understanding the ecology and management of wildlife. A conventional method of estimating age in wild animals is counting annuli formed in the cementum of teeth. This method has been used in bears despite some disadvantages, such as high invasiveness and the requirement for experienced observers. In this study, we established a novel age estimation method based on DNA methylation levels using blood collected from 49 brown bears of known ages living in both captivity and the wild. We performed bisulfite pyrosequencing and obtained methylation levels at 39 cytosine‐phosphate‐guanine (CpG) sites adjacent to 12 genes. The methylation levels of CpGs adjacent to four genes showed a significant correlation with age. The best model was based on DNA methylation levels at just four CpG sites adjacent to a single gene, SLC12A5, and it had high accuracy with a mean absolute error of 1.3 years and median absolute error of 1.0 year after leave‐one‐out cross‐validation. This model represents the first epigenetic method of age estimation in brown bears, which provides benefits over tooth‐based methods, including high accuracy, less invasiveness, and a simple procedure. Our model has the potential for application to other bear species, which will greatly improve ecological research, conservation, and management.
ISSN:1755-098X
1755-0998
DOI:10.1111/1755-0998.13788