Human MSX1 domain and mutation map. A) The positions of disease-associated human mutations are indicated by vertical arrowheads above the domain structure for human MSX1. Missense mutations (e.g., V114G) are described by the wild-type amino acid (e.g., V), the position within the human MSX1 protein (e.g., 114), and the mutation at each site (e.g., G). Nonsense mutations are indicated by horizontal arrows that terminate over the position of the introduced stop codon. Frameshift mutations are indicated by horizontal arrows terminating at the location of the mutation followed by a series of dots. Pink arrowheads denote mutations (M61K, Q187X, S202X, A219T) found in individuals that exhibit an ectodermal dysplasia phenotype. Red arrowheads denote mutations (E78V, G91D, G98E, V114G, G116E, P147Q, R151S, G267C, P278S) found in individuals that exhibit an orofacial cleft phenotype. B) The graph displays pairwise distances between MSX1, MSX2, and two outgroup sequences (Branchiostoma Msx and Lamprey MsxA). The lamprey MsxA was compared to MSX1 (small boxes) or MSX2 (large boxes) for each of the domain comparisons. In a similar fashion, Branchiostoma Msx was compared to MSX1 (down slanting lines) and MSX2 (up slanting lines).