To assess the replicability of the identified cis-eQTLs, we compared our results to four matched tissues from the Twins UK project34 (Supplementary Information 16). The vast majority of GTEx cis-eQTLs replicated at 5% FDR (Extended Data Fig. 13a; 84% in whole blood, 87% in subcutaneous adipose, 94% in lymphoblastoid cell lines (LCLs), and 93% in sun-protected skin). trans-eQTLs have not replicated consistently in human studies, compared to cis-eQTLs21,35–37, owing in part to insufficient statistical power and a limited number of studies with comparable tissues and cohorts, but also reflecting potential false positive associations. We tested trans-eQTLs discovered at 10% FDR in GTEx for replication in the TwinsUK data. Five hundred and sixty GTEx trans-eQTLs were testable in the four TwinsUK tissues and, of these, three trans-eQTLs replicated at 10% FDR (Supplementary Table 15). Despite the small number that individually replicated, in aggregate, the full set of trans-eQTLs demonstrated significantly greater replication than expected by chance (Wilcoxon rank sum test on association P values compared to uniform; P ≤3.05 ×10−5 for 16 tests in matched tissues; P ≤2.2 ×10−16 for 2,176
