was then scaled to a total of 1M UMIs (or transcript per million (TPM)) for each cell type/tissue. We then calculated a metric of gene expression specificity by dividing the expression of each gene in each cell type by the total expression of that gene in all cell types, leading to values ranging from 0 to 1 for each gene (0: meaning that the gene is not expressed in that cell type, 0.6: that 60% of the total expression of that gene is performed in that cell type, 1: that 100% of the expression of that gene is performed in that cell type). The top 10% most specific genes (Table S15 and Table S16) in each tissue/cell type partially overlapped for related tissues/cell types, did not overlap for unrelated tissue/cell types and allowed to cluster related tissues/cell types as expected (Figure S23 and Figure S24).
