Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock
ABSTRACT Knowledge of animal age is essential to wildlife managers for obtaining meaningful and accurate insights into demographic parameters. A common approach to aging wildlife, including bears (Ursus spp.), has been extracting a tooth during physical capture and counting the cementum annuli. Limi...
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| Format: | Article |
| Language: | English |
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Wiley
2025-08-01
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| Series: | Ecology and Evolution |
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| Online Access: | https://doi.org/10.1002/ece3.71870 |
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| author | Susannah P. Woodruff Milda Milčiūtė Juozas Gordevičius Robert Brooke Todd C. Atwood |
| author_facet | Susannah P. Woodruff Milda Milčiūtė Juozas Gordevičius Robert Brooke Todd C. Atwood |
| author_sort | Susannah P. Woodruff |
| collection | DOAJ |
| description | ABSTRACT Knowledge of animal age is essential to wildlife managers for obtaining meaningful and accurate insights into demographic parameters. A common approach to aging wildlife, including bears (Ursus spp.), has been extracting a tooth during physical capture and counting the cementum annuli. Limitations to tooth‐based aging include questionable accuracy and differing results based on the observer and laboratory. DNA methylation‐based epigenetic aging clocks have been developed for many species but not yet for polar bears (Ursus maritimus). We generated DNA methylation data from whole blood samples (n = 109) obtained during live capture operations from polar bears of known age in the Chukchi Sea and southern Beaufort Sea subpopulations. We used these samples to calibrate a species‐specific epigenetic clock to estimate polar bear chronological age from DNA methylation (DNAm) age. The final polar bear clock was highly accurate (r = 0.97) with a median absolute error of approximately 9 months. We applied the polar bear clock to 74 blood samples from live‐captured polar bears with a cementum annuli‐estimated age. Predicted age estimates for these bears ranged from 1.43 to 18.63 years compared to the estimated tooth age range of 3.23–25.27. These epigenetic clocks can be used for polar bear research and management where accurate estimates of age are needed for estimating demographic parameters. |
| format | Article |
| id | doaj-art-247dc0a149ab4a16b653e528845a45a8 |
| institution | Kabale University |
| issn | 2045-7758 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecology and Evolution |
| spelling | doaj-art-247dc0a149ab4a16b653e528845a45a82025-08-25T08:17:04ZengWileyEcology and Evolution2045-77582025-08-01158n/an/a10.1002/ece3.71870Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation ClockSusannah P. Woodruff0Milda Milčiūtė1Juozas Gordevičius2Robert Brooke3Todd C. Atwood4Marine Mammals Management US Fish and Wildlife Service Anchorage Alaska USAEpigenetic Development Clock Foundation Torrance California USAEpigenetic Development Clock Foundation Torrance California USAEpigenetic Development Clock Foundation Torrance California USAU.S. Geological Survey Alaska Science Center Anchorage Alaska USAABSTRACT Knowledge of animal age is essential to wildlife managers for obtaining meaningful and accurate insights into demographic parameters. A common approach to aging wildlife, including bears (Ursus spp.), has been extracting a tooth during physical capture and counting the cementum annuli. Limitations to tooth‐based aging include questionable accuracy and differing results based on the observer and laboratory. DNA methylation‐based epigenetic aging clocks have been developed for many species but not yet for polar bears (Ursus maritimus). We generated DNA methylation data from whole blood samples (n = 109) obtained during live capture operations from polar bears of known age in the Chukchi Sea and southern Beaufort Sea subpopulations. We used these samples to calibrate a species‐specific epigenetic clock to estimate polar bear chronological age from DNA methylation (DNAm) age. The final polar bear clock was highly accurate (r = 0.97) with a median absolute error of approximately 9 months. We applied the polar bear clock to 74 blood samples from live‐captured polar bears with a cementum annuli‐estimated age. Predicted age estimates for these bears ranged from 1.43 to 18.63 years compared to the estimated tooth age range of 3.23–25.27. These epigenetic clocks can be used for polar bear research and management where accurate estimates of age are needed for estimating demographic parameters.https://doi.org/10.1002/ece3.71870age estimationchronological ageDNA methylationepigeneticspolar bearwildlife management |
| spellingShingle | Susannah P. Woodruff Milda Milčiūtė Juozas Gordevičius Robert Brooke Todd C. Atwood Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock Ecology and Evolution age estimation chronological age DNA methylation epigenetics polar bear wildlife management |
| title | Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock |
| title_full | Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock |
| title_fullStr | Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock |
| title_full_unstemmed | Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock |
| title_short | Estimating Polar Bear (Ursus maritimus) Age Based on an Epigenetic DNA Methylation Clock |
| title_sort | estimating polar bear ursus maritimus age based on an epigenetic dna methylation clock |
| topic | age estimation chronological age DNA methylation epigenetics polar bear wildlife management |
| url | https://doi.org/10.1002/ece3.71870 |
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