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A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals
Published on: March 13, 2011
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Less-invasive age estimation using hair based on DNA methylation in brown bears
Shiori Nakamura1, Jumpei Yamazaki1,2, Naoya Matsumoto3
1Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Hokkaido, Japan.
Scientific Reports
|December 30, 2025
Summary
Researchers developed a new, non-invasive method to estimate the age of brown bears using DNA methylation levels found in hair. This breakthrough allows for better wildlife conservation and management by simplifying sample collection from wild populations.
Area of Science:
- Wildlife biology
- Genetics
- Conservation science
Background:
- Chronological age is crucial for wildlife life history, conservation, and management.
- DNA methylation methods offer alternatives to traditional tooth-based aging in bears.
- Current DNA methylation methods require blood or skin, limiting samples to captured or deceased animals.
Purpose of the Study:
- To establish the first hair-based age estimation model using DNA methylation in brown bears.
- To enable less-invasive age assessment in wild brown bear populations.
- To facilitate future ecological research and conservation efforts.
Main Methods:
- Collected and analyzed DNA methylation levels from brown bear hair roots using bisulfite pyrosequencing.
- Identified cytosine-phosphate-guanine (CpG) sites correlated with age near VGF, KCNK12, and ELOVL2 genes.
- Developed and validated an age estimation model using the most significant CpG sites.
Main Results:
- DNA methylation levels at specific CpG sites adjacent to VGF and KCNK12 genes correlated with chronological age.
- The best age estimation model achieved a mean absolute error of 3.2 years and a median absolute error of 2.2 years.
- The model utilized three CpG sites from two genes (VGF and KCNK12).
Conclusions:
- A novel, non-invasive method for estimating brown bear age from hair DNA methylation was successfully developed.
- This hair-based method simplifies sample collection, eliminating the need to capture bears.
- Widespread application of this technique can significantly improve understanding of wild bear population structures, aiding conservation and management.
