The Entrez Nucleotides database is a collection of sequences from several sources, including GenBank, RefSeq, and PDB. The number of bases grows at an exponential rate. As of April 2004, there are over 38,989,342,565 bases. Human Genome Explore human genome resources or browse the human genome sequence using the Map Viewer.    Building the human genome The Human Genome Reference DNA Sequence was completed in April 2003. The current version is listed as a build number on the Genome View page and includes an accompanying set of statistics and release notes.   The chromosomal locations of several genes believed to be associated with the human BRCA1 gene implicated in breast cancer, highlighted using the Map Viewer query "BRCA1" (build 35).