Fig. 2.

Urethral morphology in newborn males and females with conditional deletions of Fgfr2. Lineage tracing (A-D,M-P) and histological sections (E-L,Q-X) of the external genitalia in newborn male (A-L) and female (M-X) Fgfr2 conditional mutants. Urethral internalization is disrupted in Fgfr2^EndoΔ (F,J) and Fgfr2^EctoΔ (H,L) males. Fgfr2^EctoΔ males (H,L) and females (T,X) develop severe hypospadias. Dashed lines in A-D and M-P indicate planes of section in E-L and Q-X, respectively. Black arrows mark the internal urethral tube, black triangles indicate the penile raphe, yellow arrows denote an endodermal epithelial cord, and red triangles mark hypospadic urethral openings. Histological images were converted to grayscale using Adobe Photoshop. Scale bars: 100 μm.