GenBankFlatfile

GenBankFlatfile is a text-based format used to store and exchange biological sequence data, including nucleotide and protein sequences, as well as their annotations. It is a widely used standard in bioinformatics and molecular biology, maintained by the National Center for Biotechnology Information (NCBI). The format is designed to be both human-readable and machine-readable, making it suitable for both manual inspection and automated processing.

Each GenBankFlatfile entry consists of several sections, each starting with a specific keyword followed by a colon. The first section is the LOCUS, which provides basic information about the sequence, such as its length, type, and strand. The next section is the DEFINITION, which contains a brief description of the sequence. Following this are the ACCESSION, VERSION, KEYWORDS, SOURCE, REFERENCE, FEATURES, and BASE COUNT sections, each providing specific details about the sequence and its annotations.

The FEATURES section is particularly important, as it contains detailed information about the sequence's structure and function. Each feature is described by a key, such as CDS (coding sequence) or gene, followed by its location and any associated qualifiers. The BASE COUNT section provides a tally of the number of each nucleotide in the sequence, while the ORIGIN section contains the actual sequence data.

GenBankFlatfile entries are typically accessed through the NCBI's online databases, such as GenBank and RefSeq, where they can be searched, retrieved, and analyzed. The format is also used by various bioinformatics tools and software packages for sequence analysis, annotation, and comparison.