Chromatin Structure Simulator (2D)

This 2D canvas diagram morphs a simulated chromatin strand through the same four-level packaging hierarchy used to fit two metres of DNA inside a cell nucleus: a bare double helix winds into nucleosome "beads on a string", the beaded chain coils into a flattened 30-nm solenoid, and the coil condenses into a chromosome-like rod, with the compaction ratio at each stage computed live from the nucleosome repeat length (core 147 bp plus an adjustable linker). A second control switches the fibre between open euchromatin and densely packed heterochromatin, tracking how that switch changes whether a marked gene locus stays reachable by the transcription machinery — a compact, formula-driven view of how chromatin packing regulates gene expression.