Chromosome 20 is one of the 23 pairs of
chromosome
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
s in
human
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
s. Chromosome 20 spans around 66 million
base pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
s (the building material of
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
) 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
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: prote ...
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 functio ...
). 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
Arterial tortuosity syndrome is an extremely rare congenital connective tissue condition disorder characterized by tortuosity, elongation, stenosis, or aneurysms in major and medium-size arteries including the aorta.
Signs and symptoms
Major ma ...
*
Adenosine deaminase deficiency
*
Alagille syndrome
Alagille syndrome (ALGS) 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 patter ...
*
Galactosialidosis -
CTSA
*
Maturity onset diabetes of the young
Maturity or immaturity may refer to:
* Adulthood or age of majority
* Maturity model
** Capability Maturity Model, in software engineering, a model representing the degree of formality and optimization of processes in an organization
* Developme ...
type 1
*
Neuronal ceroid lipofuscinosis
Neuronal ceroid lipofuscinosis is a family of at least eight genetically separate neurodegenerative lysosomal storage diseases that result from excessive accumulation of lipopigments (lipofuscin) in the body's tissues. These lipopigments are made ...
*
Pantothenate kinase-associated neurodegeneration
*
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 Heterochromia iridum, one blue eye and one brown ey ...
*
CARASAL
Cytogenetic band
References
External links
*
*
{{DEFAULTSORT:Chromosome 20 (Human)
Chromosomes (human)
*