FIGURE 2.

Marker gene classification algorithm. The algorithm classifies genes with <4 cell types as Indeterminate due to insufficient data to analyze the gene unless the gene was examined against the same cell type in ≥4 separate analyses. Significant marker gene score (i.e., at least 0.5) for at least two-thirds of publications considered for each gene-cell type pair. The number of significant gene-cell type pairs per a given gene is “X”. 1) If X = 0, the gene is not a marker gene for any cell type, 2) If X = 1, the gene is a marker gene for one cell type, 3) If X ≥ 2, then the gene is a marker gene for more than one cell type. When X ≥ 2, if the gene is marker gene for multiple cell types from the same higher-level cell type (ex: connective tissue cells), then the gene is a marker gene for the higher-level cell type. When X ≥ 2, if the gene is marker gene for multiple cell types from at least 2 higher-level cell types (ex: connective tissue cells and T cells), then the gene is a non-marker gene due to lack of specificity across publications.