RNA Velocity: Single-Cell Trajectory Vector Field

RNA velocity is the technique single-cell genomics uses to turn one static snapshot of a tissue into a prediction of where each cell is heading next. This simulator integrates the real unspliced/spliced mRNA splicing-kinetics ODEs for a population of cells moving along a bifurcating differentiation trajectory: a shared progenitor trunk that splits into two committed fates once cells pass a branch point. Each cell's instantaneous RNA velocity — the rate of change of its spliced mRNA, ds/dt = β·u − γ·s — is rendered as a 3D arrow and also drives its motion along the embedding, exactly mirroring how tools like scVelo turn per-gene kinetics into the streamline arrows biologists overlay on a UMAP plot. Adjust transcription, splicing and degradation rates to see how each kinetic parameter reshapes the speed and sharpness of commitment.