Figure 1.

Generation of chimeras by morula aggregation. Wild-type or orJ morulae were aggregated overnight with morulae from the Yfp line at a ratio of 1:1 or 2:1. Blastocysts were injected into recipient pseudopregnant females. Embryos were harvested at select times and staged according to Theiler [103]. Abbreviations: wt, wild type.