Genomic comparisons and the adaptive basis of brain size plasticity and chromosomal instability in the Eurasian common shrew
Sorex araneus, the Eurasian common shrew, has seasonal brain size plasticity (Dehnel's phenomenon) and many intraspecific chromosomal rearrangements. Genomic contributions to these traits, however, remain unknown. We couple a chromosome-scale genome assembly with seasonal brain transcriptomes to discover relationships between molecular evolution and both traits. While Positively Selected Genes (PSGs) enriched the Fanconi anemia DNA repair pathway (FANCI, FAAP100), which is likely involved in chromosomal rearrangements by preventing the accumulation of chromosomal aberrations, genes under positive selection or showing seasonal differential expression in the brain implicate neurogenesis (PCDHA6, SOX9, Notch signaling) and metabolic regulation (VEGFA, SPHK2) as key mechanisms underlying Dehnel's phenomenon. We also find that both positively selected and differentially expressed genes in the hippocampus are overrepresented near S. araneus evolutionary breakpoints. This relates both positive selection and differential expression to accessible chromatin configuration, suggesting that chromosomal rearrangements are integral to adaptive evolution and the regulation of brain size plasticity.
Authors
- Liliana M. Dávalos (ORCID: https://orcid.org/0000-0002-4327-7697)
- Nivesh Jain (ORCID: https://orcid.org/0000-0002-8134-2904)
- Alan Tracey (ORCID: https://orcid.org/0000-0002-4805-9058)
- Dominik von Elverfeldt (ORCID: https://orcid.org/0000-0002-6219-3528)
- K. N. Dechmann Dina
- William R. Thomas (ORCID: https://orcid.org/0009-0002-3858-2440)
- John D. Nieland (ORCID: https://orcid.org/0000-0001-7423-0122)
- Cecilia Baldoni (ORCID: https://orcid.org/0009-0008-1341-9456)
- Laia Marín-Gual (ORCID: https://orcid.org/0000-0003-1480-0976)
- Angélique Corthals (ORCID: https://orcid.org/0000-0002-5610-2992)
- Tatiana Tilley (ORCID: https://orcid.org/0009-0001-9277-7743)
- Erich Jarvis
- Diana Moreno Santillan
- David A. Ray
- Marta Farré
- Jo Wood
- Ying Sims
- Linelle Abueg
- Jacquelyn Mountcastle
- Jennifer Balacco
Institutions
- Universitat Autònoma de Barcelona (ES)
- Texas Tech University (US)
- Howard Hughes Medical Institute (US)
- University of Konstanz (DE)
- Smith College (US)
- University of Kent (GB)
- University Medical Center Freiburg (DE)
- Wellcome Sanger Institute (GB)
- Max Planck Institute of Animal Behavior (DE)
- Stony Brook University (US)
- Rockefeller University (US)
- Aalborg University (DK)
- John Jay College of Criminal Justice (US)
- University of California, Berkeley (US)
Publication Details
- Journal
- Molecular Biology and Evolution
- Published
- 2026-01-08
- DOI
- https://doi.org/10.1093/molbev/msag006
- Primary Topic
- Genetic diversity and population structure
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Stony Brook University
- University of Massachusetts Amherst