Fig. 2. Gastrulation phenotype of Chrd^-/- embryos. (A) Wild-type and (A') mutant embryos at early somite stage. In the mutant, the body is reduced and the allantois (al) proportionally enlarged. (B-D') Sections through wild-type (B-D) and mutant embryos (B'-D') at the levels indicated in A and A'. Note the poorly differentiated neural plate (np) of the mutant (B') and its lack of trunk mesoderm (C'). (D') The increase in extra-embryonic mesodermal cells in the allantois of the mutant. so, somite.