Songbird Takes Flight in Single-Cell Genomics. Figure credit: Benjamin Wesley. Artwork: Jennifer Jones. Diagram showing the three step process that Songbird uses to estimate how many DNA copies are in individual cells. The tool first looks for regions where the amount of DNA changes. It then compares how the individually sequenced DNA fragments stack on top of each other and compares it to distant fragments. Then it removes estimation errors. Finally, Songbird plots per-cell data showing each cell's overall chromosome count and unique changes that define the differences between each cancer cell.