Data from: Seasonal brain regeneration and chromosome instability are linked to selection on DNA repair in Sorex araneus

Sorex araneus, the Eurasian common shrew, has seasonal brain size
plasticity (Dehnel’s phenomenon) and abundant intraspecific chromosomal
rearrangements, but genomic contributions to these traits remain unknown.
We couple a chromosome-scale genome assembly with seasonal brain
transcriptomes to discover relationships between molecular changes and
both traits. Positively selected genes enriched the Fanconi anemia DNA
repair pathway, which prevents the accumulation of chromosomal
aberrations, and is likely involved in chromosomal rearrangements (FANCI,
FAAP100). Genes involved in neurogenesis show either signatures of
positive selection (PCDHA6), seasonal differential expression in the
cortex and hippocampus (Notch signaling), or both (SOX9), suggesting a
role for cellular proliferation in seasonal brain shrinkage and regrowth.
Both positive selection and evolutionary upregulation in the shrew
hypothalamus of VEGFA and SPHK2 indicate adaptations in hypothalamic
metabolic homeostasis have evolved together with Dehnel’s phenomenon.
These findings reveal genomic changes central to the evolution of both
chromosomal instability and cyclical patterns in brain gene expression
that characterizes mammalian brain size plasticity.