Since INSD (the International Nucleotide Sequence Databases) had a rule to limit the sequence length for 1 entry to less than 350 kbp, DDBJ divided some long sequences during the process of their submission. Such divided sequences were assigned the accession numbers respectively, and were registered as piece entries. To inform this existence of piece entries, we made a CON(Contig/Constructed) entry, and released the information for the construction joined piece entries.
In June 2004, INSD removed the limitation of sequence length. In accordance with this removal, DDBJ plans to revise such divided sequences into a single entry for consolidation of the information.
DDBJ revises CON and piece entries as follows;
  • The accession number assigned to CON entry would be remained in the revised entry.
  • Piece entries would be suppressed and their accession numbers would be kept as the secondary accession numbers* in the revised entry.
  • Sequences and features described in piece entries would be taken over to the revised entry.
  • The revised entry would be transferred from CON to the corresponding taxonomic division.
* Even after these revisions, when you use our retrieval tools such as getentry, you can get the revised entry by the search with accession numbers of both CON and piece entries.
Please see the following site about CON entry in detail.