Labs / Biology
Morphogen Gradient
A signaling molecule leaks from the head end of an embryo and spreads down the tissue, forming a smooth concentration gradient. Each cell switches on a different gene depending on how much morphogen it senses — so a single chemical carves the body into stripes. Drag the colored threshold lines, or turn the source and diffusion knobs, and watch the boundaries slide.
λ —x₁ —x₂ —x₃ —
What to try
- Lower the source strength. Which region shrinks first — the head or the tail?
- Switch from a steep to a broad gradient. Why do all three stripe boundaries move outward at once?
- Drag the T₂ line up until it passes T₁. What happens to the Thorax region, and does that make biological sense?
- Turn on molecular noise. If cells read a jittery concentration, how sharp can a stripe boundary really be?
- Can you find source and threshold settings where the Abdomen never forms at all?