Several additional aspects of the gene expression measurements correlated with cis-eQTL replication rate. Cis-eQTL replication rate was significantly associated with mean gene expression level and, independently, inter-individual expression coefficient of variation (Figure S10; multivariate logistic regression chi-squared p-value = 3.44×10−3 and 1.41×10−4, respectively); more highly expressed and highly variable genes were more likely to replicate. Further, we found that expression variance unexplained by age, sex, race, and surrogate variables was negatively correlated with expression level (Spearman's rho = −0.302, p-value<2×10−16). These data suggest greater measurement accuracy at higher expression levels that leads to more robust eQTL identification.
