AB1 File

What are AB1 files and how to open them

Are you having problems opening an AB1 file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AB1 files.

What is an AB1 file?

An .AB1 file is an ABIF - Applied Biosystems Inc. Format file.

The ABIF (Applied Biosystems Inc. Format) file with extension .ab1 is a binary data format used to store output from Sanger DNA sequencing. Devices known as capillary sequencers, made by Applied Biosystems (Thermo Fisher Scientific), write .ab1 files when they perform a sequencing run. The file contains the raw fluorescence measurements from the four chemical dyes used to read DNA bases (representing A, T, C, G), together with processed information such as the inferred DNA base sequence, quality scores for each base, and metadata about the run including instrument settings and sample identifiers.

After the sequencer generates an .ab1 file, the file is used by sequencing analysis software for visualization, editing and downstream processing. Scientists often open it in chromatogram viewer tools to see the electropherogram (trace plot of fluorescence vs time), trim poor-quality ends, compare forward and reverse reads, or assemble consensus sequences. The file also supports validation, archival, or conversion to simpler formats like FASTA when only the DNA sequence is needed.

Technical structure: the file begins with the ASCII letters "ABIF", followed by version and header fields that point to a directory of tagged data entries. These entries use named tags (four-character names) and typed values; for larger data items such as the trace intensities, the tag points to a data block elsewhere in the file. Core tags include signal data for the four dye channels, base call data, quality scores and peak positions.

How to open AB1 files

We have identified two AB1 openers that are compatible with this specific type of AB1 file.

Programs that open ABIF - Applied Biosystems Inc. Format files

Last updated: January 22, 2025

Various apps that use files with this extension

These apps are known to open certain types of AB1 files. Remember, different programs may use AB1 files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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