Hyunji Lee1, Steven A. Vokes1
1Department of Molecular Biosciences, University of Texas at Austin, 100 E. 24th Street, Stop A5000, Austin, TX 78712, USA
Corresponding author: Steven A. Vokes
Hedgehog signaling has traditionally been considered to be a morphogen for digits. In this issue of Developmental Cell, Zhu et al. show that a brief exposure to Sonic Hedgehog is sufficient for digit specification, and this finding suggests that it is not acting as a direct morphogen but rather as an initiator of this process.