Fig. 2

Molecular and cellular heterogeneity within the developing mammary epithelium. a t-SNE and ternary plots of C57BL/6-derived mammary epithelial cells from E18.5 embryos (n = 49 rudiments). Stromal contamination (see Fig. S2A) has been removed. Both plots show the same cells with the same cluster colors. In the ternary plot, each cell is positioned according to the proportion of basal, LP, or ML signature genes expressed by that cell. The three vertices of the plot correspond to cells expressing basal genes only, LP genes only, or ML genes only. Cells expressing equal numbers of basal, LP and ML genes are in the center of the plot. b Same as in a but for mammary epithelial cells from pre-pubertal C57BL/6 mice (2 weeks; n = 32 mice; cluster resolution 0.01). c Same as in a but for mammary epithelial cells from C57BL/6 adult mice (10 weeks; n = 5 mice; cluster resolution 0.2). d t-SNE and ternary plots of all cells from E18.5, pre-pubertal, and adult mice (as shown in a–c) after Seurat integration. Cells clustered with resolution 0.45. e Same plots as in d but colored according to developmental stage. f Box plots of lineage-specific expression signatures for the same cells and clusters as in d. Each epithelial cell was interrogated with the expression signatures for the human basal, LP, and ML cell types. Vertical axis shows average expression of cell population signature genes as log2 counts per million. g Diffusion maps of E18.5, pre-pubertal, and adult mammary glands cells according to developmental stage (left) and cell clusters (right)