A five-phase state machine drives a fixed cell cycle: interphase → prophase → metaphase → anaphase → telophase/cytokinesis, each with its own duration scaled by the speed slider. At the start of every cycle, a fresh set of chromosome pairs is built and, with the probability set by the error-rate slider, exactly one pair is flagged for nondisjunction.
P(error this cycle) = errorRate / 100
if error pair: both sister chromatids -> same pole
daughterA = pairs - 1(error) + 2(error) = pairs + 1
daughterB = pairs - 1(error) + 0 = pairs - 1
- Division speed — multiplies the rate at which the phase timer advances.
- Chromosome pairs — how many sister-chromatid pairs align on the metaphase plate next cycle.
- Nondisjunction error rate — per-cycle probability that one pair fails to separate at anaphase.
When a nondisjunction event fires, both sister chromatids of the flagged pair are pulled to the same pole instead of splitting evenly, so one daughter cell ends up with one extra chromosome (trisomy-like) and the other with one fewer (monosomy-like) — the live readout below the canvas reports the exact chromosome count each daughter cell ends the cycle with, so the aneuploidy is directly countable, not just implied. Click any chromosome during prophase or later to track it through the rest of the cycle.