Making a GenBank Entry – Nucleic Acid Sequence Information

A GenBank entry follows a specific format that contains essential information about a DNA or RNA sequence along with associated metadata. Here is a detailed breakdown of the format of a GenBank entry:

1. LOCUS Line:
   • The LOCUS line provides information about the sequence’s unique identifier, sequence length, molecule type (DNA, RNA, etc.), and other key details.
   • It includes fields such as locus name, sequence length, molecule type, sequence type (linear or circular), and the date the entry was last updated.
2. DEFINITION Line:
   • The DEFINITION line describes the sequence and provides a brief summary of its characteristics, such as the organism it belongs to and any relevant annotations or features.
3. ACCESSION Line:
   • The ACCESSION line contains the primary accession number assigned to the sequence. It serves as a unique identifier for the entry in the GenBank database.
4. VERSION Line:
   • The VERSION line provides additional information about the accession number, including version number and date of the entry. It helps track updates and revisions to the sequence data.
5. KEYWORDS Line:
   • The KEYWORDS line lists specific keywords or terms that describe the sequence, allowing for easier searching and categorization of the entry.
6. SOURCE Line:
   • The SOURCE line specifies the organism or source from which the sequence was obtained. It typically includes the organism’s scientific name, common name, and taxonomic information.
7. REFERENCE Lines:
   • The REFERENCE lines provide bibliographic references to published articles or other sources that describe the sequence or related experiments. Each reference is numbered and includes details such as authors, title, journal, volume, page numbers, and publication year.
8. FEATURES Section:
   • The FEATURES section describes various features and annotations present in the sequence. It includes information on genes, coding regions, exons, introns, regulatory elements, and other biologically significant regions.
   • Each feature is defined by a feature key (e.g., gene, CDS, exon) followed by location information (start and end positions) and additional qualifiers such as product name, function, or note.
9. ORIGIN Line:
   • The ORIGIN line contains the actual nucleotide sequence data, typically represented as a series of nucleotide residues.
   • The nucleotides are presented in groups of ten, with the numbering indicated on the left side.
10. // (Double Slash):
    • The double slash indicates the end of the entry, marking the completion of the sequence data.

In addition to these primary elements, a GenBank entry may also include other optional sections like the COMMENT section for additional notes or remarks, the FEATURES table summarizing feature locations, and the CONTIG section for genome assembly information.

The GenBank format adheres to specific guidelines established by the International Nucleotide Sequence Database Collaboration (INSDC). It ensures consistency, interoperability, and easy exchange of sequence data among various biological databases.

Overall, the detailed format of a GenBank entry provides a comprehensive and standardized representation of sequence information, annotations, and metadata associated with a DNA or RNA sequence.