Surface Ectoderm Morphogenesis Figure 2. Ancestral and founder cells of the surface ectoderm. Examples of clones dispersed along the entire SE observed in E14.5 LaacZ embryos. (A)–(J9) non-SE-restricted clones classified from biggest to smallest. (K–K9) the biggest SE-restricted clone. (L–L9) the biggest non SE- restricted clone. (M–M999) Superimposition of (B–B999), (D–D999), (F–F999), (H–H999), and (J–J999); note the lack of labelling in the most dorsal region of SE delimited by the lines. (A), (C), (E), (G), (I) in toto X-gal staining. (B), (D), (F), (H), (J) drawings of their SE contribution. doi:10.1371/journal.pone.0004353.g002 PLoS ONE | www.plosone.org 5 February 2009 | Volume 4 | Issue 2 | e4353