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Fig. 1. Expression of ß-galactosidase in embryos injected at the one-cell
stage. Two representative embryos, 1-5 (A-D) and 1-4 (E-H) are shown. (A,E)
Whole mounts and (B-D,F-H) Hematoxylin and Eosin-stained sections. Almost all
parts of the embryos were positive for X-gal staining (A,B,E-F). (C,D,G,H)
Higher magnifications of B and F respectively. (H) Derivatives of primitive
endoderm (arrows) did not show X-gal staining. Scale bars: 300 µm (A,E),
150 µm (B,F), 30 µm (C,G).