Fig. 7. Histological comparison of female reproductive tracts. (A) Wild-type uterus showed single columnar epithelial cell layer (arrow), and contained endometrial glands (G) in the stromal cell layer (asterisk). (B) The A11^-/- D11^+/+ mutant uterus had fewer glands and a thinner stromal cell layer than wild type, but its epithelium and stromal tissue resembled the wild-type uterus morphologically. (C) The A11^13hd/13hd D11^+/+ mutant uterus showed an absence of glands, a multi-layered epithelium and a more fibrous stromal layer, all consistent with a posteriorization to cervix. (D) The wild type cervical canal showed a multi-layered squamous epithelium and a fibrous stromal layer with a lower cell density than seen in the uterus.