was more specific than the second, we kept the more specific pair (e.g., nose vs. nasal mucosa, quadriceps muscle vs. skeletal muscle). There were two clusters of highly correlated tissues for which we decided to remove the entire cluster, not keeping any of the tissues, because these clusters had very strong but biologically implausible correlations. The first such cluster was made up of eyelids, conjunctiva, anterior eye segment, tarsal bones, foot bones, and bones of the lower extremity. The second such cluster was made up of connective tissue, bone and bones, skeleton, and bone marrow. After pruning, this data set contained 152 tissues, listed in Table S3.
