Chromosome 20 is one of the 23 pairs of
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s in
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
s. 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
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
. 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
DNA annotation or genome annotation is the process of identifying the locations of genes and all of the coding regions in a genome and determining what those genes do. An annotation (irrespective of the context) is a note added by way of explanati ...
their predictions of the
number of genes on each chromosome varies (for technical details, see
gene prediction
In computational biology, gene prediction or gene finding refers to the process of identifying the regions of genomic DNA that encode genes. This includes protein-coding genes as well as RNA genes, but may also include prediction of other functi ...
). 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.
[ ]
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
Adenosine deaminase deficiency (ADA deficiency) is a metabolic disorder that causes immunodeficiency. It is caused by mutations in the ADA gene. It accounts for about 10–15% of all cases of autosomal recessive forms of severe combined immuno ...
*
Alagille syndrome
Alagille syndrome is a genetic disorder that affects primarily the liver and the heart. Problems associated with the disorder generally become evident in infancy or early childhood. The disorder is inherited in an autosomal dominant pattern, and t ...
*
Fatal familial insomnia
Fatal insomnia is an extremely rare genetic (and even more rarely, sporadic) disorder that results in trouble sleeping as its hallmark symptom. The problems with sleeping typically start out gradually and worsen over time. Eventually, the patien ...
*
Galactosialidosis -
CTSA
*
Maturity onset diabetes of the young type 1
*
Neuronal ceroid lipofuscinosis
*
Pantothenate kinase-associated neurodegeneration
*
Transmissible spongiform encephalopathy
Transmissible spongiform encephalopathies (TSEs) are a group of progressive and fatal conditions that are associated with prions and affect the brain and nervous system of many animals, including humans, cattle, and sheep. According to the most ...
(prion diseases)
*
Waardenburg syndrome
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes (or one blue eye and one brown eye), a white forelock ...
Cytogenetic band
References
External links
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*
{{DEFAULTSORT:Chromosome 20 (Human)
Chromosomes (human)
*