Selective Sweep & Genetic Hitchhiking Simulator

When a beneficial mutation rises to fixation under positive selection, it doesn't travel alone — every neutral variant physically linked to it on the same chromosome gets dragged along too, a phenomenon population geneticists call genetic hitchhiking. This simulator runs a real individual-based Wright-Fisher model over a 41-site chromosome segment: each generation, offspring are sampled with probability proportional to fitness at a single selected locus, while linked neutral sites are free to recombine away with a probability that grows with genetic distance from that locus. Watch the population's colour-coded ancestry converge to a single lineage right around the selected site while distant sites stay a diverse mosaic, and track the beneficial allele's frequency, the collapsing diversity at the locus, and the width of the resulting low-diversity haplotype block — the same genomic signature real scans use to find recent positive selection, such as around the human lactase-persistence gene.