Fig. 7: The union of candidate cell-type homologs, identified among three species (mouse, zebrafish and frog) by two strategies.

a, Candidate cell-type homologs were identified either by comparison of transcriptomes via nonnegative least-squares regression or by examining overlap between upregulated candidate key TFs (key TF). Nominated pairings were manually reviewed, and a subset retained based on biological plausibility. Colors of nodes indicate the species of a given cell type, and colors of edges indicate which approach(es) identifies the pairing. Sets of connected candidate cell-type homologs are further grouped by germ layer or developmental system. b, Selected examples of ‘three-way’ pairwise cell-type homology from different germ layers in the above network. Upregulated candidate key TFs shared by each pair of species are listed, with the subset shared by all three species in red font. Of note, key TFs shared by mouse (mm) versus zebrafish (zf) and mm versus frog (xp) are shown by mouse gene symbols, whereas key TFs shared by zf versus xp are shown by zebrafish gene symbols. NNLS, nonnegative least squares.