A, C, E, G , and H were probed with the anti-sense strand and B, D , and F were probed with the sense strand. G is the anterior view of the frontal lobes and the nasal placode of a D3.5 embryo. Faint staining is also seen in the whole frontal lobe. J is a section through the right eye in H , showing staining in the retina. K is a transverse section through the trunk at the level of leg buds.
L shows that staining in the mandibular arch is restricted to the cells of the mesenchyme.