Fig. 6. Diagrammatic representation of signals that operate in the epithelium and in the mesenchyme within the globular process and maxillary prominence at the time of primary palate fusion. (A) Region illustrated in (B) is enclosed in box. (B) The differences in expression of genes in the epithelium in relation to possible mesenchymal signals are illustrated. Coloured boxes indicate gene families that are expressed in different regions of the epithelium. Abbreviations: EMT, epithelial-mesenchymal transformation; FNM, frontonasal mass; LNP, lateral nasal prominence; Mx, maxillary prominence; NP, nasal pit; PCD, programmed cell death.