To address these questions, we conducted a combined study of twin heritability of expression and eQTLs that is the largest yet reported (3.4X the size of the next largest twin eQTL report8,15,30), providing high resolution. Gene expression was assessed in peripheral blood, with careful attention to sample collection, cell type heterogeneity, bias, and control of experimental error. Our goals were to: (1) describe and evaluate the heritability of all transcripts measured in peripheral blood; (2) identify a comprehensive list of local and distant eQTLs and evaluate their characteristics and replicability; and (3) assess their biomedical relevance.
