Chromosome 2 (human)


In the human genome, chromosome 2 is the second largest of the 23 chromosomes. It is a submetacentric chromosome, found within group A of the human karyotype. As with all autosomes, somatic cells carry two copies of chromosome 2, while gametes carry only one copy.

Chromosome 2 is approximately 237 Mbp (million base pairs) in length, comprising ~8% of the haploid genome
Chromosome 2 has approximately 1491 genes

Evolutionarily, it is believed that the human chromosome 2 is the result of an end-to-end fusion of two chromosomes in the chimpanzee genome (chimps have 24 chromosomes). Evidence for this includes sequence homology between human chromosome 2 and two chimp chromosomes, remnants of a second centromere on human chromosome 2, and remnants of telomere sequences within human chromosome 2 where the chromosomes are likely to have fused at their ends.

Significant genes (and some related genetic diseases) on chromosome 2 include:

  • ABCG5 and ABCG8 (genetic locus: 2p21) encode sterolin-1 and -2, respectively, which are two halves of the ATP-binding casette (ABC) transporter responsible for sterol absorption and excretion. Mutations in these genes are responsible for the disorder of lipid metabolism, sitosterolaemia

  • NR4A2 (genetic locus: 2q22-q23) encodes a nuclear receptor which acts as an intracellular transcription factor with a key role in the maintenance of the dopaminergic system of the brain. Defects in the gene are associated with numerous neurological and psychiatric conditions including Parkinson's disease, schizophrenia and manic depression

  • MSH2 (genetic locus: 2p21) a gene commonly associated with hereditary colorectal cancer and some endometrium cancers

  • BMPR2 (genetic locus: 2q33-q34) encodes a serine/threonine receptor kinase which binds ligands involved in osteogenesis and cell differentiation. Mutation in the gene has been liked to primary pulmonary hypertension.