Figure 7. Compensation and gene expression.

Plot showing the existence of a statistically very significant correlation (Pearson correlation coefficient $r=0.47$ and p-value, ${\displaystyle p=8.1{10}^{-13}}$) between the expression level of Kcnip2, encoding the KChIP2 accessory $\beta$ subunits that interact with Kv4.2 channels (${\text{I}}_{\text{to},\text{f}}$) and of Cacna1c, a gene encoding the $\alpha$1C subunit of the Cav1.2 L-type calcium channels (${\text{I}}_{\text{Ca},\text{L}}$) across 206 mice. Cardiac gene expression was measured in $106$ control (Pre-ISO) strains and 21 days after injection of isoproterenol (post-ISO) in 100 HMDP strains (a smaller number due to higher mortality of certain strains). Note that the significant correlation holds when considering separately pre-ISO (blue points, $r=0.59$, ${\displaystyle p=2{10}^{-11}}$) and post-ISO (red points, $r=0.42$, ${\displaystyle p=1.5{10}^{-5}}$) data. Lines show best fits of a linear model for pre-ISO (blue), post-ISO (red), and pre- and post-ISO combined (black). Expression data is taken from Santolini et al. (2018) and is averaged over all microarray probes for each gene.