Tracy: basecalling, alignment, assembly and deconvolution of sanger chromatogram trace files

BMC Genomics. 2020 Mar 14;21(1):230. doi: 10.1186/s12864-020-6635-8.


Background: DNA sequencing is at the core of many molecular biology laboratories. Despite its long history, there is a lack of user-friendly Sanger sequencing data analysis tools that can be run interactively as a web application or at large-scale in batch from the command-line.

Results: We present Tracy, an efficient and versatile command-line application that enables basecalling, alignment, assembly and deconvolution of sequencing chromatogram files. Its companion web applications make all functionality of Tracy easily accessible using standard web browser technologies and interactive graphical user interfaces. Tracy can be easily integrated in large-scale pipelines and high-throughput settings, and it uses state-of-the-art file formats such as JSON and BCF for reporting chromatogram sequencing results and variant calls. The software is open-source and freely available at, the companion web applications are hosted at

Conclusions: Tracy can be routinely applied in large-scale validation efforts conducted in clinical genomics studies as well as for high-throughput genome editing techniques that require a fast and rapid method to confirm discovered variants or engineered mutations. Molecular biologists benefit from the companion web applications that enable installation-free Sanger chromatogram analyses using intuitive, graphical user interfaces.

Keywords: Alignment; Chromatogram; PCR; Sanger sequencing; Variant calling.

MeSH terms

  • Computational Biology / methods*
  • High-Throughput Nucleotide Sequencing / methods
  • Humans
  • Sequence Analysis, DNA / methods*
  • Software
  • User-Computer Interface
  • Web Browser