August 2009: NCBI released an updated version of the human genome reference genome assembly and updated annotation for all available assemblies. The reference assembly update includes modifications to all chromosomes and adds 9 alternate loci to the reference assembly definition; the updated assembly, named GRCh37, was provided by the Genome Reference Consortium (GRC). The previous version of the reference genome assembly, NCBI Build 36.3, can still be accessed for Map Viewer display and for BLAST. For additional information about changes, statistics, and the status of the CCDS project please refer to:

• Release Notes
• Statistics
• CCDS Project

The NCBI Map Viewer provides graphical displays of features on the human genome sequence assembly as well as cytogenetic, genetic, physical, and radiation hybrid maps. Extensive documentation is provided to describe the resource features and methods used, tutorials, and statistics.

Map features that can be seen along the sequence include genes, transcripts, NCBI contigs (the 'Contig' map), the BAC tiling path (the 'Component' map), STSs, FISH mapped clones, ESTs and transcripts from several different organisms, Gnomon predicted gene models, and more.

You can find genes or markers of interest by submitting a query against the whole genome, or a chromosome at a time. Use the Advanced Search form for more complex queries. Results are indicated both graphically, as tick marks on the ideogram, and in a tabular format. The results table includes links to a chromosome graphical view where the gene or marker can be seen in the context of additional data. For genes, a particularly useful display includes the Gene, Ab initio (e.g., the Gnomon predicted models), and UniGene sequence maps. You can also browse a chromosome by clicking on a chromosome link in the ideogram above. Use the "Maps & Options" window, available on individual chromosome displays, to configure your display.

Please note that other genomes can also be viewed in the NCBI Map Viewer resource. The Map Viewer Home Page provides a current list. Additional organism-specific web pages are listed on the Genomic Biology site.

Available Documentation:

• NCBI Handbook: Map Viewer chapter - resource description
• NCBI Handbook: Map Viewer Exercises - tutorials and examples
• Map Viewer Help - details about navigation and customizing your display
• Genome Assembly - description of genome assembly and annotation process
• Gnomon - description of NCBI's Hidden Markov Model (HMM) ab initio prediction program