Expression of pluripotent markers and colony-forming efficiency of embryonic FACs. Both AoM- and YS-derived FACs express Oct-4 and Nanog (A). CFU-F assay shows that AoM-derived FACs possess the highest colony-forming efficiency (26.7%), while those of UGRs (13.3%) and YS (14.4%) are much lower (B,C). Of note, colonies from YS are much smaller than those from AoM or UGRs. Original magnification: (A) ×200.