Colocalization of gene signatures of corresponding human and mouse mammary cell subsets. (a) Multidimension scaling (MDS) plot showing clear separation of the MaSC-enriched (MS), the two luminal (luminal progenitor, LP; and mature luminal, ML), and stromal (str) cell subpopulations in both human (h) and mouse (m) mammary glands. (b) MDS plot after normalization for dimension 1 in (a), representing the differences across species. This demonstrates colocalization of analogous human and mouse mammary cell subsets. (c) Dot plots demonstrating the highest colocalization of gene signatures between corresponding subsets compared with other subsets.