Figure 3

Grading embryonic stem cell colonies. Examples of ESC classification into one of the three grades: Grade Good (GG), Average (GA), or Poor (GP). In GG colonies the area occupied by pluripotent cells is >70% of the entire colony (a). Approximately 60% of the colony is occupied by pluripotent cells in GA colonies (b), and a GP colony features only ~20% of pluripotent cells (c). Scale = 30 μm.