In this study, we investigated 149 human livers surgically removed from Caucasian donors to identify statistically significant associations between genetic polymorphisms and mRNA expression levels at a genome-wide scale. Although our study was similar in design and technology to the former study,16 the set of human liver samples had no overlap and differed in many aspects including ethnicity, sampling procedures, availability and completeness of clinical data. We focus in this paper on genes involved in absorption, distribution, metabolism and excretion (ADME) of drugs to allow for more detailed analyses, which resulted in a smaller set (∼20%) of truly replicated eQTLs and a larger set (∼80%) of unique eQTLs. This demonstrated that the genetical genomics approach is useful to identify novel genotype–phenotype relationships, and that a single study is insufficient to uncover all existing eQTLs in a given tissue.
