Before revision:  In terms of the gene regulation networks, this congruence is understood as the successive addition of downstream modules, either as feedforward or feedback , while the upstream feedforward network shapes the boundary condition for the downstream dynamics, based on the maternal morphogen gradient. Acquisition of a novel developmental mode was due to mutational change in the upstream network to alter the boundary condition .
After revision:  In terms of the gene regulation networks, this congruence is understood as the successive addition of downstream modules, either as feedforward or feedback , while the upstream feedforward network that reads the morphogen gradient. By using a pattern generated by the upstream feedforward network as a boundary condition, downstream networks form later stripe patterns. These epochal changes in development and evolution are represented as same bifurcations in dynamical-systems theory, and this agreement of bifurcations lead to the evolution-development congruences. Violation of the upstream network to alter the boundary condition .