Gonadal development in DMRT1-mutant embryos. Gross morphology of gonads (A) and Müllerian ducts (B) in ZD+ZD+ and ZD+W embryos and ZD+ZD-and ZD-W DMRT1-mutant embryos (n = 3–7 embryos per genotype). Immuno-sections from right (R) and left (L) gonads from E13.5 wild-type and DMRT1-mutant embryos (C–F). Expression of DMRT1, aromatase (AROM) and AMH (C, E) and SOX9, FOXL2, and of PGC-specific marker (VASA) (D, F). A minimum of three embryos of each genotype were examined. Arrows indicate gonads in A and Müllerian ducts in B. Asterisks indicate Wolffian ducts in B. c, cortex; m, medulla. (G) Relative gene expression of DMRT1 and of testis and ovary markers in gonads of E8.5 wild-type and DMRT1-mutant embryos. Individual expression levels were calculated relative to levels in ZD+ZD+. Five replicates on pools of two gonads per genotype. Bars represent mean ± SD. Different letters specify statistically significant groups, P < 0.05.