Effect of VHSv infection on the expression of genes from the IGF-IGFBP system at 3 stages of rainbow trout development, contextualized by data for genes involved in muscle growth and host defense. A–D, Examples of genes significantly regulated in response to VHSv, including those down-regulated: IGF-II (A) and IGFBP-1A2 (B) and up-regulated: IGFBP-6A2 (C) and IGFBP-1A1 (D) (not significant, see text). For all these graphs, mean transcript levels + SD are provided on a scale allowing comparison across genes (n = 3–5 for treatments, n = 5 for PBS controls). Numbers provided next to data points are the fold change differences (treatment/control). Accompanying details on statistics including other genes is presented in Table 3. E, Heatmap depicting results of seriation and hierarchical clustering analysis on all tested genes. F, Scatterplot of ranked expression data showing the striking coregulation of IGFBP-6A2 expression with antiviral host defense genes in control and VHSv-infected fish.