3 file types use the .fas file extension.

What is a FAS file?

Compiled script written in AutoLISP, a variation of the LISP programming language used specifically for the extension of AutoCAD software; often used for creating macros that automate common processes within AutoCAD; can be used for distributing utilities that add new features to the software.

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Category: Executable Files

FASTA Sequence File

A FAS file may also be a plain text file saved in the FASTA format, a file format used for storing nucleic acid and protein sequences. It contains one or more sequences, which include a sequence identification code and the sequence. Biochemistry students, academics, and professionals may use FAS files to store and process bioinformatics information, such as the genomes of different species.

David J. Lipman and William R. Pearson created the FASTA format and released it in 1985. It has since become a standard format for transferring sequences between applications because of its simplicity.

The FASTA format

The FASTA format is simple, consisting of the following elements:

NOTE: FAS files may be saved with other file extensions, such as .fasta ( .FASTA files) and .fa ( .FA files), but they are saved in the same FASTA format.

You can open an FAS file with various DNA applications, such as GSL Biotech SnapGene (multiplatform), Genome Compiler (multiplatform), and Heracle BioSoft DNA Baser (Windows). To open an FAS file with SnapGene, select File → Open Files... .

Opening an FAS file with a text editor

Since FAS files are saved in plain text, you can also open them with a text editor, such as Microsoft Notepad (Windows) or Apple TextEdit (Mac), or a source code editor. Keep in mind that a text editor or source editor will not display the sequence in the FAS file natively like a DNA app. Also, you may need to rename the .fas file extension to .txt for the text editor to recognize it.

When opened in a text editor or source code editor, you can modify the properties of the FAS file, including the sequence. However, if you incorrectly edit the file, you may corrupt the sequence.

Several applications, including GSL Biotech SnapGene and Heracle BioSoft DNA Baser, can convert FAS files to other formats.

For example, SnapGene can convert FAS files to the following formats:

Programs that open FAS files

Updated: October 13, 2022

QuickSilver Fast Save Lisp File

Compiled Lisp ( .LSP ) file saved in the "Fast Save Lisp Format" by Interleaf or QuickSilver; contains compiled code that can be executed by the program; may be generated by selecting either the DTK→Compile→Buffer or DTK→Lisp→Compile menu commands.

FAS files are also called FASL (Fast Load) files.

NOTE: BroadVision acquired Interleaf in January 2000 and later renamed the InterLeaf software to QuickSilver. Aurea later acquired BroadVision.

Programs that open FAS files

Updated: October 5, 2009