Human assembly and gene annotation

Assembly

This site provides a data set based on the December 2013 Homo sapiens high coverage assembly GRCh38 from the Genome Reference Consortium. This assembly is used by UCSC to create their hg38 database. The data set consists of gene models built from the genewise alignments of the human proteome as well as from alignments of human cDNAs using the cDNA2genome model of exonerate.

This release of the assembly has the following properties:

• contig length total 3.4 Gb.
• chromosome length total 3.1 Gb (excluding haplotypes).

It also includes 261 alt loci scaffolds, mainly in the LRC/KIR complex on chromosome 19 (35 alternate sequence representations) and the MHC region on chromosome 6 (7 alternate sequence representations).

Watch a video on YouTube about patches and haplotypes in the Human genome.

Patches

As the GRC maintains and improves the assembly, patches are being introduced. Currently, assembly patches are of two types:

• Novel patch: new sequences that add alternative sequence at a loci and will remain as haplotypes in the next major assembly release by GRC
• Fix patch: sequences that correct the reference sequence and will replace the given region of the reference assembly at the next major assembly release by GRC.

Other assemblies

Gene annotation

The Ensembl human gene annotations have been updated using Ensembl's automatic annotation pipeline. The updated annotation incorporates new protein and cDNA sequences which have become publicly available since the last GRCh38 genebuild (December 2013).

In the current release, we continue to display a joint gene set based on the merge between the automatic annotation from Ensembl and the manually curated annotation from Havana. See the statistics table, right, for the corresponding GENCODE version number. The Consensus Coding Sequence (CCDS) identifiers have also been mapped to the annotations. More information about the CCDS project.

Updated manual annotation from Havana is merged into the Ensembl annotation every release. Transcripts from the two annotation sources are merged if they share the same internal exon-intron boundaries (i.e. have identical splicing pattern) with slight differences in the terminal exons allowed. Importantly, all Havana transcripts are included in the final Ensembl/Havana merged (GENCODE) gene set.

• Detailed information on genebuild (PDF)

The T2T-CHM13v2.0 assembly and annotation is available through Ensembl Rapid Release.

More information

General information about this species can be found in Wikipedia.