It is designed to handle single gene sequences, sets of related sequences in population or phylogenetic studies, and complete chromosomes or bacterial genomes. Recent enhancements make it convenient for genome sequencing centers to annotate their records with Sequin and submit the resulting ASN.1 file to GenBank.
Many genome centers maintain feature locations and annotations in an internal database.
It also allows multiple intervals per feature in order to represent the multiple exons in a spliced mRNA, for example. Once the sequence and annotation have been read in, Sequin's validator can be used to check for internal stops in coding regions and use of consensus splice sites. The entire process can be automated for multiple chromosomes in a genome with the utility tbl2asn, which produces ASN.1 from pairs of table and sequence files. At minimum, all definition lines must contain an identifier for the sequence, called the SeqId. Other information about the biological source of the organism can also be encoded on the definition line of the sequence and is used to build the record.