(A) Hierarchical clustering of expression identified 12 distinct clusters, of which seven clusters (1, 4, 5, 6, 7, 9, 10) comprising of 394 genes, showed variation consistent with seasonality or Dehnel’s phenomenon. (B) Functional characterization of these genes using KEGG GO pathways found an enrichment of 14 pathways (p<0.05), many of which have been implicated in hypothalamic control of homeostatic maintenance, including, relaxin signaling, neuroactive ligand-receptor interaction, HIF-1 signaling, and PI3K-Akt signaling.

(A) Volcano plot of significant (padj<0.05) differentially expressed genes (colored) between phenotypic extremes of hypothalami size change (spring vs autumn) plotted by log fold-change. (B) Pathway enrichment analysis identified 15 pathways to be enriched for differentially expressed genes, including pathways in cancer and apoptosis (downregulated). (C) Patterning of gene expression across seasons of Dehnel’s phenomenon for genes found in the cancer (all) and apoptosis (red) pathways, including BCL2L1 (dashed). (D) Cell viability of Mustela putorious furo neural cell lines exposed to four treatments: scrambled BCL2L1 overexpression, BCL2L1 overexpression, heat with scrambled BCL2L1 overexpression, and heat with BCL2L1 overexpression. Heat significantly reduced the cell viability compared to controls but was not rescued by BCL2L1 overexpression.

(A) Heatmap and boxplots of genes with shrew-specific upregulation compared to other mammals associated with processes including calcium signaling, autophagy, neurological functions, (B) metabolic homeostasis and environmental sensing.

Significant shrew-specific upregulation of genes associated with calcium signaling pathways, blood brain barrier plasticity, food intake and leptin response, and other related functions.

Boxplots of CCDC22 showing both evolutionary upregulation (A) in the shrew and differential expression between spring and autumn individuals, as found in three other genes (KCNS1, LMX1A, PAQR4) (B), which have been implicated in the development and progression of human neurological disorders.