MIT SIS LAB
Population 0
Generation 0
Divisions 0
Mutations 0

What Mitosis Lab is

Mitosis Lab is a free, browser-based cell-lineage simulator. It starts with one cell and lets you watch it divide, again and again, into a branching family tree. Each division is stochastic, drawn from a mean interval with jitter, and each daughter inherits a slightly mutated copy of its mother's traits. The colony that grows is a genealogy you can read: colour marks a sub-lineage, and distance from the centre marks a generation. It is built for biology students, educators, and anyone who likes a living system to poke at, and it runs entirely in your browser with nothing to install.

How to use it

  1. Press play to start the founding cell dividing.
  2. Drag mutation rate up to watch sub-lineages fan out into new colours, or down to hold a single hue.
  3. Change the division interval and jitter to move between a slow, synchronised colony and a fast, staggered one.
  4. Set a seed and share the URL. The seed and every parameter travel in the link, so whoever opens it sees the exact same run.
  5. Let the population reach its cap to trigger the colony-saturated summary, then reseed for a fresh tree.

FAQ

What is a cell-lineage tree?
It is the branching diagram biologists use to trace which cell came from which. The root is the founding cell; every fork is one division into two daughters. Mitosis Lab draws that tree live as the colony grows.
Is the simulation scientifically accurate?
It is a teaching model, not a research tool. It captures two real ideas faithfully: division timing is stochastic rather than clockwork, and traits are inherited with drift. It does not model a specific organism, cell-cycle checkpoints, or cell death.
What do the colours mean?
Colour is an inherited trait that drifts when a mutation fires. A branch that shifts from green toward cyan or magenta marks a sub-lineage carrying that mutation, so you can trace a mutation back to the cell where it started.
Why is every run reproducible?
The whole simulation is a pure function of its seed and parameters, driven by a seeded PRNG and a fixed timestep. The same seed and knobs always produce the same tree, at any frame rate, which is why a shared link recreates a run exactly.
Does it work on a phone?
Yes. The stage fills the top of the screen and the controls become a bottom sheet, with touch targets sized for a thumb.

More by Charlie Krug → apps.charliekrug.com