Feb 02, 2024
GRCr8: A new rat reference assembly is released!
May 09, 2022
Genome Assemblies
The GRC has built tools to facilitate the curation of genome assemblies based on the sequence overlaps of long, high quality sequences (clones and PCR products, not short sequence reads). The GRC currently supports production of assemblies for human, mouse or zebrafish. If your assembly data fits this model and you are interested in using these tools, please contact us. Subscribe to the grc-announce email list to receive email notification for all GRC assembly updates.
Human
The human genome assembly was produced as part of the Human Genome Project (HGP). The previous assembly (NCBI36) was the last one produced by the HGP and was described in 2004 (PMID: 15496913); this was the starting point for the GRC. The assembly is based largely on assembling overlapping clone sequences.
| Current major assembly | GRCh38 |
|---|---|
| Regions with alternate loci | 178 |
| Assembly N50 | 67,794,873 bp |
| Remaining gaps | 875 |
| Patch release version | p14 |
| Patches released | FIX: 164, NOVEL: 90 |
More human assembly statistics...
Mouse
The GRC has produced an updated assembly (GRCm38). This is an update of the last MGSC assembly (MGSCv37) which was described in 2009 (PMID: 19468303). The primary assembly is based on assembling overlapping BAC clones derived from the C57BL/6J strain and several loci have sequence available from other strains.
| Current major assembly | GRCm39 |
|---|---|
| Regions with alternate loci | 0 |
| Assembly N50 | 106,145,001 bp |
| Remaining gaps | 347 |
| Patch release version | None |
| Patches released | FIX: 0, NOVEL: 0 |
More mouse assembly statistics...
Zebrafish
The zebrafish genome assembly was produced at the Wellcome Sanger Institute. The last assembly produced from the original project was Zv9 and was described in 2013 (PMID: 23594743). This assembly is the starting point for the GRC. The assembly is based on assembling overlapping BAC clones and integrating these sequences with the whole genome shotgun assembly.
| Current major assembly | GRCz11 |
|---|---|
| Regions with alternate loci | 607 |
| Assembly N50 | 7,379,053 bp |
| Remaining gaps | 18,736 |
More zebrafish assembly statistics...
Rat
GRCr8 was generated by Dr. Peter Doris (University of Texas Health Science Center at Houston) with colleagues Theodore Kalbfleisch (University of Kentucky) and Melissa Smith (University of Louisville) in the NHGRI-funded "Inbred Rat Genomes Project". The assembly is based on PacBio HiFi sequences from a BN/NHsdMcwi male rat. The assembly was gap filled using contigs from the PacBio CLR reads produced for mRatBN7.2. Additional short read genomic sequence from a BN/NHsdMcwi rat in the Hybrid Rat Diversity Program at the Medical College of Wisconsin were used for assembly polishing.
| Current major assembly | GRCr8 |
|---|---|
| Regions with alternate loci | 0 |
| Assembly N50 | 137,014,596 bp |
| Remaining gaps | 220 |
More rat assembly statistics...
Chicken
The chicken genome assembly was produced by the International Chicken Genome Consortium. Gallus_gallus-5.0 is the latest assembly produced from this project. This assembly is the starting point for the GRC. It is comprised primarily of WGS contigs, into which overlapping genomic clones from the same DNA source have been integrated.
| Current major assembly | GRCg6a |
|---|---|
| Regions with alternate loci | 0 |
| Assembly N50 | 20,785,086 bp |
| Remaining gaps | 946 |
More chicken assembly statistics...