Bio::asn1::entrezgene and bio::asn1::sequence are regular expression-based parsers for ncbi entrez gene genome databases ().

they parse asn.1-formatted entrez gene records and ncbi sequences, returning data structures that contain all data items from the gene records or the sequence records.

the parser will report error & line number if input data does not conform to the ncbi entrez gene genome or ncbi sequence annotation file format.

bio::asn1::sequence is basically a modified version of the high-performance bio::asn1::entrezgene parser. however this standalone module exists since it is more efficient to keep sequence-specific code out of entrezgene.pm.