🧪 Sanger Sequencing: Chain-Termination Simulation

This simulator runs the real biochemistry behind Sanger (chain-termination) DNA sequencing: a randomly generated template strand is copied by a large population of independent, parallel DNA-polymerase extension reactions, each one a base-by-base race against a tunable probability that a chain-terminating dideoxynucleotide (ddNTP) gets incorporated instead of a normal dNTP, permanently stopping that single copy at that exact position. Across thousands of copies this produces a real spread of terminated fragment lengths, which the simulator sorts by size — exactly as capillary electrophoresis does, shortest fragments first — and colour-codes by terminating base using the authentic four-colour Sanger convention (A green, T red, G black, C blue) to draw a live chromatogram trace. Reading the trace shortest-to-longest reconstructs the true complementary sequence of the template, and the ddNTP:dNTP ratio and population-size controls let you reproduce the real trade-off between read length and signal dropout that governs an actual sequencing reaction.