<p>A, B, C. Slight differences of C57BL/6 ntES colonies cultured in control ES medium (A), PD- (B) and SC1-supplemented media (C). Scale bar = 50 µm. Arrow indicates the slight differentiation morphology in control ES medium. D, E, F. Histograms of cell cycle distribution of C57BL/6 ntES cells in the present in control ES medium (D), PD- (E) and SC1-supplemented media (F).</p