Morphogenetic Field — Positional Information Wolpert

Morphogens diffuse from source to sink, creating concentration gradients. Cells read their position via threshold concentrations and differentiate into distinct cell types — the "French Flag" model.

Morphogen Parameters

Diffusion constant D: 0.5 Degradation rate λ: 0.3 Source concentration: 1.0 Threshold 1: 0.5 Threshold 2: 0.2 Model:

Pattern

λ scale length: —

Blue boundary: —

White boundary: —

Cells: 3 zones

Steady-state gradient:
c(x) = c₀·e^(-x/λ_D)
λ_D = √(D/λ)

Cells differentiate when:
c > θ₁ → Type A
θ₂ < c ≤ θ₁ → Type B
c ≤ θ₂ → Type C

Morphogenetic Fields — Positional Information (Wolpert 1969)

Morphogen Parameters

Pattern