Examples of fluorescently labeled mouse embryos. In all three cases, the time between the first and the second image is 2 h. (A,A') A CAG-TAG embryo in which the epiblast and visceral endoderm is visualized by expression of a membrane-localized TdTomato (magenta). (B,B') A KikGR embryo in which two regions of the epiblast have been labeled by photoconversion (magenta). The green fluorescence is the nonphotoconverted KikGR. (C,C') An R26R-eYFP reporter embryo in which epiblast cells are labeled (yellow) through the mosaic expression of MORECre. Scale bar, 50 μm.