Diverging transposon activity among polar bear sub-populations inhabiting different climate zones

Godden, Alice M., Rix, Benjamin T. and Immler, Simone (2025) Diverging transposon activity among polar bear sub-populations inhabiting different climate zones. Mobile DNA, 16 (1). ISSN 1759-8753

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Abstract

A new subpopulation of polar bears (Ursus maritimus) was recently discovered in the South-East of Greenland. This isolated colony inhabits a warmer climate zone, akin to the predicted future environments of polar bears with vastly reduced sea ice habitats, rendering this population of bears particularly important. Over two-thirds of polar bears will be extinct by 2050 with total extinction predicted by the end of this century, therefore understanding possible mechanisms of adaptation via genomic analyses and preservation are critical. Transposable elements (TEs) are mobile elements that may play a role in an adaptive response to environmental challenges. We analysed transcriptome data from polar bear sub-populations in cooler North-East (NEG) and warmer South-East Greenland (SEG) to compare TE activity between the two populations and its correlation with temperature and associated changes in gene expression. We identified activity hotspots in the genome of regions with significantly differentially expressed TEs. LINE family TEs were the most abundant, and most differentially expressed and divergent in the SEG population compared to reference TEs. We report a significant shift in TE activity and age, with younger more abundant TEs in the SEG populations. Differentially expressed genes in SEG populations were linked to Foxo signalling, ageing and metabolic pathways. Our results provide insights into how a genomic response at the TE level may allow the SEG subpopulations to adapt and survive to climate change and provides a useful resource for conservation in polar bears.

Item Type:	Article
Additional Information:	Data availability: RNA-seq data was deposited by Laidre et al. 14 under ENA accession PRJNA669153. All R and python scripts used to analyse this data can be found in the following Github repository: https://github.com/alicegodden/polar bear/. Metadata used for the files accessed can be found in Supplementary file 2. The datasets supporting this article have been uploaded as part of the supplementary material in files 1-8. Supplementary files include all raw counts data from RNA-seq analyses, DESeq2 outputs for differential gene and TE expression with different models and can be found here: https://gith ub.com/alicegodden/polarbear/tree/main/supplementary_data. Full length Supplementary File 6, and other input files used in the bioinformatic pipelines also provided at Zenodo here: https://doi.org/10.5281/zenodo.17573136 ( https://zenodo.org/records/17573136). We also provide Suppl. File 9 which includes metadata for samples analysed in the RNA-seq analysis, and Suppl. File 10 with the configuration settings for our RNA-seq on our local cluster for full replication.
Uncontrolled Keywords:	adaptive response,polar bear,thermal stress,transposable elements,ursus,molecular biology,sdg 13 - climate action ,/dk/atira/pure/subjectarea/asjc/1300/1312
Faculty \ School:	Faculty of Science > School of Biological Sciences
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	13 Jan 2026 13:30
Last Modified:	19 Jan 2026 01:08
URI:	https://ueaeprints.uea.ac.uk/id/eprint/101591
DOI:	10.1186/s13100-025-00387-4

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