TY - JOUR
T1 - Genomic comparisons and the adaptive basis of brain size plasticity and chromosomal instability in the Eurasian common shrew
AU - Thomas, William R.
AU - Lama, Tanya M.
AU - Baldoni, Cecilia
AU - Marín-Gual, Laia
AU - Moreno Santillán, Diana
AU - Farré, Marta
AU - Abueg, Linelle
AU - Balacco, Jennifer
AU - Fedrigo, Olivier
AU - Formenti, Giulio
AU - Jain, Nivesh
AU - Mountcastle, Jacquelyn
AU - Tilley, Tatiana
AU - Sims, Ying
AU - Tracey, Alan
AU - Wood, Jo
AU - Ray, David A.
AU - Von Elverfeldt, Dominik
AU - Nieland, John
AU - Corthals, Angelique P.
AU - Ruiz-Herrera, Aurora
AU - Dechmann, Dina K.N.
AU - Jarvis, Erich
AU - Dávalos, Liliana M.
N1 - Publisher Copyright:
© The Author(s) 2026. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.
PY - 2026/2/1
Y1 - 2026/2/1
N2 - 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.
AB - 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.
KW - Dehnel’s phenomenon
KW - chromosomal evolution
KW - cortex
KW - evolutionary breakpoints
KW - highly contiguous genome assembly
KW - hippocampus
KW - shrew
UR - https://www.scopus.com/pages/publications/105029932431
U2 - 10.1093/molbev/msag006
DO - 10.1093/molbev/msag006
M3 - Article
C2 - 41517999
AN - SCOPUS:105029932431
SN - 0737-4038
VL - 43
JO - Molecular Biology and Evolution
JF - Molecular Biology and Evolution
IS - 2
M1 - msag006
ER -