Chromosome 20 is one of the 23 pairs of chromosomes in humans. Chromosome 20 spans around 66 million base pairs (the building material of DNA) and represents between 2 and 2.5 percent of the total DNA in cells. Chromosome 20 was fully sequenced in 2001 and was reported to contain over 59 million base pairs. Since then, due to sequencing improvements and fixes, the length of chromosome 20 has been updated to just over 66 million base pairs.
Genes Number of genes The following are some of the gene count estimates of human chromosome 20. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.
Estimated by Protein-coding genes Non-coding RNA genes Pseudogenes Source Release date CCDS 516 — — 2016-09-08 HGNC 519 191 297 2017-05-12 Ensembl 540 594 247 2017-03-29 UniProt 550 — — 2018-02-28 NCBI 555 487 333 2017-05-19
Gene list
The following is a partial list of genes on human chromosome 20. For complete list, see the link in the infobox on the right.
Diseases and disorders The following diseases are some of those related to genes on chromosome 20:
Albright's hereditary osteodystrophy Arterial tortuosity syndrome Adenosine deaminase deficiency Alagille syndrome Galactosialidosis - CTSA Maturity onset diabetes of the young type 1 Neuronal ceroid lipofuscinosis Pantothenate kinase-associated neurodegeneration Waardenburg syndrome type 4B CARASAL Creutzfeldt-Jakob disease
Cytogenetic band
+ G-bands of human chromosome 20 in resolution 850 bphsGenome Decoration Page, NCBI. Ideogram data for Homo sapience (850 bphs, Assembly GRCh38.p3). Last update 2014-06-03. Retrieved 2017-04-26. Chr. Arm"p": Short arm; "q": Long arm. BandFor cytogenetic banding nomenclature, see article locus. ISCNstartThese values (ISCN start/stop) are based on the length of bands/ideograms from the ISCN book, An International System for Human Cytogenetic Nomenclature (2013). Arbitrary unit. ISCNstop Basepairstart Basepairstop Staingpos: Region which is positively stained by G banding, generally AT-rich and gene poor; gneg: Region which is negatively stained by G banding, generally CG-rich and gene rich; acen Centromere. var: Variable region; stalk: Stalk. Density 20 p 13 0 333 gneg 20 p 12.3 333 513 gpos 75 20 p 12.2 513 624 gneg 20 p 12.1 624 915 gpos 75 20 p 11.23 915 1164 gneg 20 p 11.22 1164 1275 gpos 25 20 p 11.21 1275 1441 gneg 20 p 11.1 1441 1608 acen 20 q 11.1 1608 1774 acen 20 q 11.21 1774 1927 gneg 20 q 11.22 1927 2051 gpos 25 20 q 11.23 2051 2232 gneg 20 q 12 2232 2439 gpos 75 20 q 13.11 2439 2578 gneg 20 q 13.12 2578 2758 gpos 25 20 q 13.13 2758 3077 gneg 20 q 13.2 3077 3299 gpos 75 20 q 13.31 3299 3382 gneg 20 q 13.32 3382 3493 gpos 50 20 q 13.33 3493 3770 gneg
References
External links