Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 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 and representing almost eight percent of the total DNA in human

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 2 contains the HOXD

homeobox A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. For instance, mutations in a homeobox may change large-scale anatomical features of the full- ...

gene cluster.Vega Homo sapiens genome browser: HoxD cluster on Chromosome 2
/ref>

Chromosomes

Humans have only twenty-three pairs of chromosomes, while all other extant members of

Hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ea ...

have twenty-four pairs. It is believed that Neanderthals and

Denisovans The Denisovans or Denisova hominins ) are an extinct species or subspecies of archaic human that ranged across Asia during the Lower and Middle Paleolithic. Denisovans are known from few physical remains and consequently, most of what is kn ...

had twenty-three pairs. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.It has been hypothesized that Human Chromosome 2 is a fusion of two ancestral chromosomes
by Alec MacAndrew; accessed 18 May 2006. The evidence for this includes: * The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the chimpanzee, has nearly identical

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

s to human chromosome 2, but they are found in two separate chromosomes. The same is true of the more distant

gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four ...

and

orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the gen ...

.Human and Ape Chromosomes
; accessed 8 September 2007. * The presence of a

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

centromere The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers ...

. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere in the q21.3–q22.1 region. * The presence of vestigial

telomere A telomere (; ) is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes. Although there are different architectures, telomeres, in a broad sense, are a widespread genetic feature mo ...

s. These are normally found only at the ends of a chromosome, but in chromosome 2 there are additional telomere sequences in the q13 band, far from either end of the chromosome.

Genes

Number of genes

The following are some of the gene count estimates of human chromosome 2. Because researchers use different approaches to genome annotation their

prediction A prediction (Latin ''præ-'', "before," and ''dicere'', "to say"), or forecast, is a statement about a future event or data. They are often, but not always, based upon experience or knowledge. There is no universal agreement about the exac ...

s of the number of genes on each chromosome vary. 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.

List of genes

The following is a partial list of genes on human chromosome 2. For complete list, see the link in the infobox on the right.

p-arm

Partial list of the genes located on p-arm (short arm) of human chromosome 2:

q-arm

Partial list of the genes located on q-arm (long arm) of human chromosome 2:

Related disorders and traits

The following diseases and traits are related to genes located on chromosome 2: *

2p15-16.1 microdeletion syndrome 2p15-16.1 microdeletion is an extremely rare genetic disorder caused by a small deletion in the short arm of human chromosome 2. First described in two patients in 2007, by 2013 only 21 people have been reported as having the disorder in the med ...

Autism The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...

Alport syndrome Alport syndrome is a genetic disorder affecting around 1 in 5,000-10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect ...

Alström syndrome Alström syndrome (AS), also called Alström–Hallgren syndrome, is a very rare autosomal recessive genetic disorder characterised by childhood obesity and multiple organ dysfunction. Symptoms include early-onset type 2 diabetes, cone-rod dy ...

Amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

* Brachydactyly type D * Cleft chin *

Congenital hypothyroidism Congenital hypothyroidism (CH) is thyroid hormone deficiency present at birth. If untreated for several months after birth, severe congenital hypothyroidism can lead to growth failure and permanent intellectual disability. Infants born with congen ...

* Crigler-Najjar types I/II *

Dementia with Lewy bodies Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior, cognition, movement, and regulation of automatic bodily functions. Memory loss is not always an early symptom. The disease worsens over time an ...

* Ehlers–Danlos syndrome * Ehlers–Danlos syndrome, classical type * Ehlers–Danlos syndrome, vascular type *

Fibrodysplasia ossificans progressiva Fibrodysplasia ossificans progressiva (; FOP; also called Münchmeyer disease and formerly called myositis ossificans progressiva or Stoneman disease) is an extremely rare connective tissue disease in which fibrous connective tissue such as mus ...

Gilbert's syndrome Gilbert syndrome (GS) is a syndrome in which the liver of affected individuals processes bilirubin more slowly than the majority. Many people never have symptoms. Occasionally jaundice (a slight yellowish color of the skin or whites of the eyes ...

* Harlequin type ichthyosis *

Hemochromatosis Iron overload or hemochromatosis (also spelled ''haemochromatosis'' in British English) indicates increased total accumulation of iron in the body from any cause and resulting organ damage. The most important causes are hereditary haemochromatos ...

Hemochromatosis type 4 Hemochromatosis type 4 is a hereditary iron overload disorder that affects ferroportin, an iron transport protein needed to export iron from cells into circulation. Although the disease is rare, it is found throughout the world and affects people ...

Hereditary nonpolyposis colorectal cancer Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is an autosomal dominant genetic condition that is associated with a high risk of colon cancer as well as other cancers including endometrial cancer (second most common), ovary, ...

Infantile-onset ascending hereditary spastic paralysis Spasticity () is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles. ...

* Juvenile primary lateral sclerosis *

Lactose intolerance Lactose intolerance is a common condition caused by a decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pa ...

* Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency *

Lowry-Wood syndrome Lowry-Wood syndrome, also simply known as LWS, is a very rare genetic disorder which is characterized by dysplasia of the epiphysis, low height/short stature, microcephaly, developmental delay, intellectual disabilities, and congenital nystagmus. ...

* Maturity onset diabetes of the young type 6 * Mitochondrial trifunctional protein deficiency *

Nonsyndromic deafness Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body. Genetic changes are related to the follo ...

* Photic sneeze reflex * Primary hyperoxaluria * Primary pulmonary hypertension * Sitosterolemia (knockout of either ABCG5 or ABCG8) * Sensenbrenner syndrome *

Synesthesia Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who rep ...