Understanding genetic control for gene expression in human livers is important to elucidate the mechanism underlying health and disease. Wang et al. carried out the first genome-wide analysis in liver tissues of a Han Chinese population and observed 1,669 genetic loci significantly associated with hepatic gene expression. The study also found that at least 41% of these alleles were significantly associated hepatic gene expression in a Caucasian population. In addition, the study revealed that disease-associated alleles and the alleles significantly involved in drug metabolism and response were more likely to control gene expression in human livers. (By Dr. Zhihai Peng, http://jmg.bmj.com/content/early/2014/03/24/jmedgenet-2013-102045 )