Transformation from juvenile to adult pigment markings in the angelfish
P. semicirculatus, for a logistic-type growth. We use
L1(
t) =
L2(
t) =
to model a domain growing exponentially initially and approaching a constant size at large time. Simulation results for the cell density show the slow insertion of new stripes as the domain grows during initial stages (
a and
b), followed by a breakup into a pattern of spots as the domain approaches its maximum size. During the breakup into spots, an intermediate phase can be seen where the pattern is a combination of stripes and spots (
d and
e). We use the Lengyel–Epstein model of the (chloride/iodide/malonic acid reaction for the chemical kinetics,
with parameter values
k1 = 10.0,
k2 = 17.6,
Du = 0.01,
Dv = 2.0,
Dn = 5.0 ×10
−5, χ
0 = 2.5 × 10
−5, and an initial domain of dimensions [0,1.58] × [0,1.58]. To force a pattern of regular stripes, we have selected initial conditions of the form shown in Fig.
6d for the morphogens.