Chromosome 2 (human)

Chromosome 2 (human)

Chromosome 2 (human)
Human chromosome 2 pair after G-banding. One is from mother, one is from father.
Chromosome 2 pair in human male karyogram.
Length (bp) 242,193,529 bp
Number of genes 2,787
Type Autosome
Centromere position Submetacentric [1]
RefSeq NC_000002
GenBank CM000664
Fusion of ancestral chromosomes left distinctive remnants of telomeres, and a vestigial centromere
Map of Chromosome 2
Ideogram of human chromosome 2. Mbp means mega base pair. See locus for other notation.

Chromosome 2 is one of the 23 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 pairs [2] (the building material of DNA) and representing almost 8% of the total DNA in cells.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 2 likely contains 1,491 genes, including those of the HOXD homeobox gene cluster.[3]


  • Evolution 1
  • Genes 2
  • Related diseases and traits 3
  • References 4


All members of Hominidae except humans, Neanderthals, and Denisovans have 24 pairs of chromosomes.[4] Humans have only 23 pairs of chromosomes. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.[5][6]

The evidence for this includes:

  • The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the chimpanzee, has near-identical DNA sequences to human chromosome 2, but they are found in two separate chromosomes. The same is true of the more distant gorilla and orangutan.[7][8]
  • The presence of a vestigial centromere. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere.[9]
  • The presence of vestigial telomeres. These are normally found only at the ends of a chromosome, but in chromosome 2 there are additional telomere sequences in the middle.[10]

Chromosome 2 is consistent with the common ancestry of humans and other apes. According to researcher J. W. IJdo, "We conclude that the locus cloned in cosmids c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the point at which two ancestral ape chromosomes fused to give rise to human chromosome 2." [10]


Among the genes located on chromosome 2 are these:

  • AGXT: alanine-glyoxylate aminotransferase (oxalosis I; hyperoxaluria I; glycolicaciduria; serine-pyruvate aminotransferase)
  • ALS2: amyotrophic lateral sclerosis 2 (juvenile)
  • COL3A1: collagen, type III, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant)
  • COL4A3: collagen, type IV, alpha 3 (Goodpasture antigen)
  • COL4A4: collagen, type IV, alpha 4
  • COL5A2: collagen, type V, alpha 2
  • CTLA4: cytotoxic T-Lymphocyte Antigen 4
  • HADHA: hydroxyacyl-Coenzyme A dehydrogenase/3-ketoacyl-Coenzyme A thiolase/enoyl-Coenzyme A hydratase (trifunctional protein), alpha subunit
  • HADHB: hydroxyacyl-Coenzyme A dehydrogenase/3-ketoacyl-Coenzyme A thiolase/enoyl-Coenzyme A hydratase (trifunctional protein), beta subunit
  • NCL: Nucleolin
  • NR4A2: nuclear receptor subfamily 4, group A, member 2
  • OTOF: otoferlin
  • PAX3: paired box gene 3 (Waardenburg syndrome 1)
  • PAX8: paired box gene 8
  • PELI1: Ubiquitin ligase
  • SLC40A1: solute carrier family 40 (iron-regulated transporter), member 1
  • SSB: Sjogren syndrome antigen B
  • TPO: thyroid peroxidase
  • TTN: titin

Genes located on the short arm of this chromosome include

Genes located on the long arm of this chromosome include

  • ABCA12: ATP-binding cassette, sub-family A (ABC1), member 12
  • BMPR2: bone morphogenetic protein receptor, type II (serine/threonine kinase)
  • TBR1: T-box, brain, 1

Related diseases and traits

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


  1. ^ "Table 2.3: Human chromosome groups". Human Molecular Genetics (2nd ed.). Garland Science. 1999. 
  2. ^  
  3. ^ Vega Homo sapiens genome browser: HoxD cluster on Chromosome 2
  4. ^ Meyer M, Kircher M, Gansauge MT, Li H, Racimo F, Mallick S, Schraiber JG, Jay F, Prüfer K, de Filippo C, Sudmant PH, Alkan C, Fu Q, Do R, Rohland N, Tandon A, Siebauer M, Green RE, Bryc K, Briggs AW, Stenzel U, Dabney J, Shendure J, Kitzman J, Hammer MF, Shunkov MV, Derevianko AP, Patterson N, Andrés AM, Eichler EE, Slatkin M, Reich D, Kelso J, Pääbo S; Kircher; Gansauge; Li; Racimo; Mallick; Schraiber; Jay; Prüfer; De Filippo; Sudmant; Alkan; Fu; Do; Rohland; Tandon; Siebauer; Green; Bryc; Briggs; Stenzel; Dabney; Shendure; Kitzman; Hammer; Shunkov; Derevianko; Patterson; Andrés; et al. (October 2012). "A high-coverage genome sequence from an archaic Denisovan individual". Science 338 (6104): 222–6.  
  5. ^ Human Chromosome 2 is a fusion of two ancestral chromosomes by Alec MacAndrew; accessed 18 May 2006.
  6. ^ Evidence of Common Ancestry: Human Chromosome 2 (video) 2007
  7. ^ Yunis and Prakash; Prakash, O (1982). "The origin of man: a chromosomal pictorial legacy". Science 215 (4539): 1525–30.  
  8. ^ Human and Ape Chromosomes; accessed 8 September 2007.
  9. ^ Avarello; et al. (1992). "Evidence for an ancestral alphoid domain on the long arm of human chromosome 2". Human Genetics 89 (2): 247–9.  
  10. ^ a b IJdo; et al. (1991). "Origin of human chromosome 2: an ancestral telomere-telomere fusion". Proc. Natl. Acad. Sci. U.S.A. 88 (20): 9051–5.