Fig. 5. The progeny of parity-induced mammary epithelial cells marked by the expression of ß-galactosidase (blue) included LREC that were doubly labeled by 5BrdU and ³HtdR (arrows) in mammary transplant outgrowths in the cleared fat pads of doubly pulsed female hosts. This indicated that during the process of expansive self-renewal some of these cells become asymmetrically dividing LREC. The red brackets outline the region of the image where the plane of section is tangential to the long axis of the duct, thus exposing the suprabasal epithelial layer. Scale bar: 10 µm.