EMBL (also known as EMBL-Bank) Nucleotide Sequence Database constitutes Europe's primary nucleotide sequence resource. (Users in the U.S. users may prefer to use NCBI GenBank site for sequence retrieval). Main sources for DNA and RNA sequences are direct submissions from individual researchers, genome sequencing projects and patent applications. The database is produced in collaboration with GenBank and the DNA Database of Japan (DDBJ). Each of the three groups collects a portion of the total sequence data reported worldwide, and all new and updated database entries are exchanged between the groups on a daily basis.