Skip to main content
Kent Academic Repository

Genomic comparisons and the adaptive basis of brain size plasticity and chromosomal instability in the Eurasian common shrew

Thomas, William R., Lama, Tanya M., Baldoni, Cecilia, Marín-Gual, Laia, Moreno Santillán, Diana, Farré, Marta, Abueg, Linelle, Balacco, Jennifer, Fedrigo, Olivier, Formenti, Giulio, and others. (2026) Genomic comparisons and the adaptive basis of brain size plasticity and chromosomal instability in the Eurasian common shrew. Molecular Biology and Evolution, 43 (2). Article Number msag006. ISSN 0737-4038. E-ISSN 1537-1719. (doi:10.1093/molbev/msag006) (KAR id:113152)

Abstract

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.

Item Type: Article
DOI/Identification number: 10.1093/molbev/msag006
Uncontrolled keywords: highly contiguous genome assembly; shrew; Dehnel’s phenomenon; evolutionary breakpoints; chromosomal evolution; cortex; hippocampus
Subjects: Q Science
Institutional Unit: Schools > School of Natural Sciences > Biosciences
Former Institutional Unit:
There are no former institutional units.
Funders: National Science Foundation (https://ror.org/021nxhr62)
Catalan Institution for Research and Advanced Studies (https://ror.org/0371hy230)
SWORD Depositor: JISC Publications Router
Depositing User: JISC Publications Router
Date Deposited: 19 Mar 2026 11:32 UTC
Last Modified: 20 Mar 2026 12:11 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/113152 (The current URI for this page, for reference purposes)

University of Kent Author Information

  • Depositors only (login required):

Total unique views of this page since July 2020. For more details click on the image.