Top 500 putative identity genes from each cell type were collected and unioned together first. Then none cell identity genes were labeled as black, and identity genes were labeled as red. Heatmap was created by using morpheus from Broad institute (https://software.broadinstitute.org/morpheus/). DAVID pathway analyses and cell type specific subnetworks were performed as previously described. In order to compare the specificity of gene expression and cell identity scores at the same level by Tau index, quantile normalization was performed. P values were calculated using Wilcoxon test.