A. Gene expression analysis by real-time PCR on day 6 EB generated from the iLhx2 ES cells comparing control EBs (−Dox) to those where Lhx2 expression was turned on at day 4 of differentiation (+Dox). B. Frequency of definitive CFCs responding to SCF/IL-6/epo in clonal assays of day 6 EBs in the presence (+Dox) or absence (−Dox) of dox, if dox was added at day 3 or 4 of differentiation, or if dox was present between day 3 and 5 of differentiation. Control is day 6 EBs generated without dox. C. Frequency of definitive CFCs responding to SCF/IL-6/epo in clonal assays of day 6, 7 and 8 EBs in the presence (−Dox) of absence (+Dox) of dox if dox was added or not at day 4 of differentiation. Hence, the following combinations were analysed: −− no dox added to the ES cells differentiation or to clonal assays of EB cells, −+ dox was added to clonal assays of day 6, 7 and 8 EB cells. +− dox was added to day 4 EB and no dox was added to clonal assays of the day 6, 7 and 8 EB cells. ++ dox was added to day 4 EBs and to the clonal assays of the day 6, 7 and 8 EB cells. Asterisks indicate where the difference in CFC between clonal assays performed in the absence or presence of dox is statistically significant, *p<0,005, **p<0,05.