The Genotype-Tissue Expression project (GTEx) was launched in 2010, in order to build a catalog of how genetic variation affects gene expression. It consists of gene expression data from a variety of tissues from post mortem donors. The first set of results was published in 2015. The data from version 8 has just been released, with the main paper published in Science describing RNA sequencing data from 49 tissues from 838 individuals. Genome Biology and Genome Medicine are happy to publish these companion articles to the project.