Genetic Linkage & Crossing Over

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 simulator renders a real 3D homologous chromosome pair (bivalent), lets you place two marked loci anywhere from 1 to 80 centiMorgans apart, and generates crossover points as a Poisson process along the chromosome exactly as the classical Haldane no-interference model predicts. Running a single meiosis animates the chiasmata and colours each locus by which parental strand it ended up on; running a batch of 200 trials accumulates an empirical recombination frequency that converges on the theoretical Haldane curve r = ½(1 − e^(−2d)) — the same relationship geneticists use to build real linkage maps from breeding data.