689 (50.7%) of the target genes are regulated by a single cis-acting SNP locus (Figure S2A, related to Figure 1); the rest are regulated by multiple loci (2 to 83). After adjusting correlated loci by stepwise feature selection (Methods), 664 genes (48.9%) are explained by multiple SNP loci (median number 4), suggesting the existence of multiple independent eQTLs. 5,669 of the 5,893 cis-acting eQTL loci are associated with one target gene, suggesting the associations are highly locus specific (Figure S2B, related to Figure 1). Cis-associations typically occur within the 2 nearest transcripts (39.8%) of the eQTL; an additional 18.9% occur between 3 to 5 nearest transcripts (Figure S2C, related to Table 1).
