Genetic Linkage & Crossing Over — 2D

Two genes on the same chromosome don't always stay together when they're passed to offspring — chromosomal crossing over during meiosis I can shuffle them into new combinations, and how often that happens depends on how far apart the genes sit. This 2D companion simulator renders a homologous chromosome pair as two ribbons, lets you place two marked loci from 1 to 160 centiMorgans apart, and generates crossover points as an independent Poisson process along the chromosome exactly as the classical Haldane no-interference model predicts. Running a single meiosis animates the chiasmata resolving and colours each locus by which parental strand it ended up on; running batches of trials — or a full automatic sweep across map distances — accumulates empirical recombination frequencies plotted live against the theoretical Haldane curve r = ½(1 − e^(−2d)), the same relationship geneticists use to build real linkage maps from breeding data.