Homo sapiens (Graphic courtesy of CBSE)

The February 2009 human reference sequence (GRCh37) was produced by the Genome Reference Consortium.

### Sample position queries

A genome position can be specified by the accession number of a sequenced genomic clone, an mRNA or EST or STS marker, a chromosomal coordinate range, or keywords from the GenBank description of an mRNA. The following list shows examples of valid position queries for the human genome. See the User's Guide for more information.

Request: | Genome Browser Response:
chr7 |  | Displays all of chromosome 7
chrUn_gl000212 |  | Displays all of the unplaced contig gl000212
chr3:1-1000000 |  | Displays first million bases of chr 3, counting from p-arm telomere
chr3:1000000+2000 |  | Displays a region of chr3 that spans 2000 bases, starting with position 1000000
RH18061;RH80175 |  | Displays region between genome landmarks, such as the STS markers RH18061 and RH80175. This syntax may also be used for other range queries, such as between uniquely determined ESTs, mRNAs, refSeqs, etc.
D16S3046 |  | Displays region around STS marker D16S3046 from the Genethon/Marshfield maps. Includes 100,000 bases on each side as well.
AA205474 |  | Displays region of EST with GenBank accession AA205474 in BRCA1 cancer gene on chr 17
AC008101 |  | Displays region of clone with GenBank accession AC008101
AF083811 |  | Displays region of mRNA with GenBank accession number AF083811
PRNP |  | Displays region of genome with HUGO Gene Nomenclature Committee identifier PRNP
NM_017414 |  | Displays the region of genome with RefSeq identifier NM_017414
NP_059110 |  | Displays the region of genome with protein accession number NP_059110
pseudogene mRNA |  | Lists transcribed pseudogenes, but not cDNAs
homeobox caudal |  | Lists mRNAs for caudal homeobox genes
zinc finger |  | Lists many zinc finger mRNAs
kruppel zinc finger |  | Lists only kruppel-like zinc fingers
huntington |  | Lists candidate genes associated with Huntington's disease
zahler |  | Lists mRNAs deposited by scientist named Zahler
Evans,J.E. |  | Lists mRNAs deposited by co-author J.E. Evans
Use this last format for author queries. Although GenBank requires the search format Evans JE, internally it uses the format Evans,J.E..

### Assembly Details

The GRCh37 build reference sequence is considered to be "finished", a technical term indicating that the sequence is highly accurate (with fewer than one error per 10,000 bases) and highly contiguous (with the only remaining gaps corresponding to regions whose sequence cannot be reliably resolved with current technology). Future work on the reference sequence will focus on improving accuracy and reducing gaps in the sequence. Statistics for the GRCh37 build assembly can be found on the NCBI Build 37.1 Statistics web page.

Note on chrM
Since the release of the UCSC hg19 assembly, the Homo sapiens mitochondrion sequence (represented as "chrM" in the Genome Browser) has been replaced in GenBank with the record NC_012920. We have not replaced the original sequence, NC_001807, in the hg19 Genome Browser. We plan to use the Revised Cambridge Reference Sequence (rCRS) in the next human assembly release.

Chromosome naming scheme
In addition to the "regular" chromosomes, the hg19 browser contains nine haplotype chromosomes and 59 unplaced contigs. If an unplaced contig is localized to a chromosome, the contig name is appended to the regular chromosome name, as in `chr1_gl000191_random`. If the chromosome is unknown, the contig is represented with the name "chrUn" followed by the contig identifier, as in `chrUn_gl000211`. Note that the chrUn contigs are no longer placed in a single, artificial chromosome as they have been in previous UCSC assemblies. See the sequences page for a complete list of hg19 chromosome names.

The nine haplotype chromosomes are:

name | accession | UCSC chr name
--- | --- | ---
HSCHR6_MHC_APD_CTG1 | GL000250.1 | chr6_apd_hap1
HSCHR6_MHC_COX_CTG1 | GL000251.1 | chr6_cox_hap2
HSCHR6_MHC_DBB_CTG1 | GL000252.1 | chr6_dbb_hap3
HSCHR6_MHC_MANN_CTG1 | GL000253.1 | chr6_mann_hap4
HSCHR6_MHC_MCF_CTG1 | GL000254.1 | chr6_mcf_hap5
HSCHR6_MHC_QBL_CTG1 | GL000255.1 | chr6_qbl_hap6
HSCHR6_MHC_SSTO_CTG1 | GL000256.1 | chr6_ssto_hap7
HSCHR4_1_CTG9 | GL000257.1 | chr4_ctg9_hap1
HSCHR17_1_CTG5 | GL000258.1 | chr17_ctg5_hap1

See the Wellcome Trust Sanger Institute MHC Haplotype Project web site for additional information on the chr6 alternate haplotype assemblies.

The Y chromosome in this assembly contains two pseudoautosomal regions (PARs) that were taken from the corresponding regions in the X chromosome and are exact duplicates:

> chrY:10001-2649520 and chrY:59034050-59363566
> chrX:60001-2699520 and chrX:154931044-155260560

Bulk downloads of the data are available from the UCSC downloads server via ftp or http. We recommend that you use rsync or ftp for downloading large or multiple files.

The hg19 annotation tracks were generated by UCSC and collaborators worldwide. See the Credits page for a detailed list of the organizations and individuals who contributed to this release.