Chromosome 2

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 and representing almost 8% of the total DNA in cells.

Structure

Chromosome 2 is likely a result of an end-to-end fusion of two ancestral chromosomes. The evidence for this includes:

• The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the bonobo, 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.
• The presence of a vestigial centromere. Normally a chromosome has just one active centromere, but in chromosome 2 there are remnants of a second centromere.
• 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.

Genes

Chromosome 2 contains over 1,400 genes, which code for various proteins and molecules in the body. Some of the genes on this chromosome include:

• ALMS1: This gene is associated with Alström syndrome.
• COL3A1: This gene codes for type III collagen, which is found in extensible connective tissues such as skin, lung, and the vascular system.
• COL5A2: This gene codes for type V collagen, which is found in tissues containing type I collagen and appears to regulate the assembly of the fibrils.

Diseases and disorders

Several diseases and disorders are associated with genes on chromosome 2, including:

• Alström syndrome
• Ehlers-Danlos syndrome
• Mucolipidosis
• Harlequin type ichthyosis
• Lactose intolerance
• Parkinson's disease

See also

• List of human chromosomes