Figure 4.

 Limb defects in Jag2^ΔDSL homozygotes. (A,B) Feet of neonatal mice. A forefoot (left) and hindfoot (right) is shown in each panel. Jag2^ΔDSL homozygous neonates (B) exhibit syndactyly of both fore- and hindlimbs, although the hindlimbs are more severely affected. (C–F) Stained skeletal preparations of neonatal limbs of a heterozygous (C) and three Jag2^ΔDSL homozygous mice (D–F). Both a fore- and a hindfoot are shown in each panel. The forefoot is on the right in C and E, and on the left in D and F. The homozygotes display several defects affecting distal phalanges, including secondary osseous fusions of both fore- and hindfeet (white arrows in D–F), primary chondrogenic fusions (black arrow in D), and terminal splitting of a distal phalanx (arrowheads in E,F).