Fig. 1. des is notch1. Morphological phenotypes of (A) wild-type and (B) desP37A embryos at about the 15-somite stage. des embryos form the first seven to nine somites but not the posterior somites. Anterior is leftwards. (C) des was mapped to linkage group 21 between z20701 and z7925, while notch1 was mapped between z27387 and z7925 (z15810). Genetic distance from the top of linkage group 21 (left) is given in cM. (D) Four independent alleles of des were sequenced. desAXO1B has a 7 bp insertion (5'-TGTGCAG-3') between bases 2738 and 2739, creating a frame-shift and premature stop, seven codons to the C terminus. desH35B has a T to A transition at base 4552, converting a Cys to a stop. desP37A has a T to A transition at base 186, creating a Leu to Gln substitution within the hydrophobic domain of the signal peptide (SP). desM145B has a G to A transition at base 6683, causing a Val to Met substitution. There are no obvious differences between these alleles in the severity of the somite phenotype. Nucleotide and amino acid sequences refer to the published wild-type sequences (Bierkamp and Campos-Ortega, 1993). TM, transmembrane domain.
