Genome Reference Consortium

NCBI is a member of the Genome Reference Consortium (GRC), an international collaboration that oversees updates and improvements to the human, mouse, and zebrafish reference genome assemblies. These reference assemblies include linear chromosome representations, unlocalized and unplaced scaffold sequences, and alternate loci scaffolds providing alternate sequence representations for genome regions too complex to be adequately represented by the linear chromosome path. The GRC produces two types of assembly updates: (1) major releases, in which chromosome coordinates are changed, and (2) minor releases, in which chromosome coordinates do not change and updates are provided as standalone patch scaffold sequences. All GRC assemblies are submitted to the International Nucleotide Sequence Database Collaboration (INSDC) databases and made publicly available. The GRC is not responsible for annotation of the reference assemblies. For information about the National Center for Biotechnology Information’s (NCBI) annotation of the GRC assemblies, please see the handbook chapter titled, “About Eukaryotic Genome Processing and Tools”.