The Graphical Fragment Assembly (GFA) is a proposed format which allow to describe the product of sequence assembly. This gem implements the proposed specifications for the GFA format described under as close as possible.

The library allows to create a RGFA object from a file in the GFA format or from scratch, to enumerate the graph elements (segments, links, containments, paths and header lines), to traverse the graph (by traversing all links outgoing from or incoming to a segment), to search for elements (e.g. which links connect two segments) and to manipulate the graph (e.g. to eliminate a link or a segment or to duplicate a segment distributing the read counts evenly on the copies).


After installation of the gem (rake install), the library can be included in the own scripts with require "rgfa". Additional functionality, which requires custom tags and additional conventions, is included in a separate part of the code named "RGFATools" and can be accessed with require "rgfatools".


A cheatsheet is available as pdf under

The full API documentation is available as pdf under or in HTML format (

The main class of the library is RGFA, which is a good starting point when reading the documentation.


The manuscript describing the library has been presented at the German Conference on Bioinformatics 2016. Currently it is under review and available as a Peer Journal preprint:

Gonnella G, Kurtz S. (2016) RGFA: powerful and convenient handling of assembly graphs. PeerJ Preprints 4:e2381v1