Fig. 2.

Digit growth results in sequential joint formation. (A) Timecourse of GDF5 expression during joint patterning. Reproduced, with permission, from Huang et al. (2016). (B) Simulations incorporating digit growth results in progressive addition of distal joints. (C) A committed zone: final timepoint of simulations that allow patterning only within a certain distance, L_P, to the distal tip; three different values of L_P are shown. (D) Adding uniform growth to the in silico digit results in distally decreasing phalanx size.