Gene induction in targeted single blastomeres.

<p>(A) <i>C. elegans</i> early embryos viewed with Nomarski optics. (B) GFP expression 3 h after irradiation of single blastomeres of 8-, 4-, and 2-cell embryos. Irradiation of ABar, ABal, ABpr, ABpl, MS, E, and C in 8-cell embryos, and of ABa, ABp, and EMS in 4-cell embryos lead to GFP expression in a cell cluster corresponding to the descendants of the respective blastomere in embryos in the late blastula stage. Irradiation of AB in 2-cell embryos leads to variable GFP expression patterns in AB descendants. Irradiation of germ-line blastomeres P1 and P2 mostly failed to induce GFP induction. Scale bar = 10 µm. (C) Lineage pattern of early cleavage in the <i>C. elegans</i> embryo.