We also observed that a substantial number of SNPs were associated with more than one gene. A total of 264 genes have eQTLs at the 0.01 permutation threshold organized in clusters of 2 or more genes, where the eQTL is identical among genes, suggesting same functional variant. Of these, 52 clusters of 2 or more genes were observed (and therefore replicated) in at least two populations and the distance to TSS of such eQTL-SNPs was larger relative to all other eQTL-SNPs for single genes. This signal suggests the presence of regulatory domains that influence multiple genes in a coordinated fashion and these tend to do so from long distances. Such coordinated regulation from distance is well known in the HOX cluster [31], but our data suggests that this may be a more general phenomenon.
