Chromosome 22 is the second smallest human chromosome and represents between 1.5% and 2% of the total DNA in cells.
- small sized chromosome
- about 50,000,000 base pairs
- about 742 genes
Gene examples of chromosome 22:
BCR (breakpoint cluster region): Within this gene is a located breakpoint for a reciprocal translocation between chromosome 22 and chromosome 9. This means that part of chromosome 9 can move to chromosome 22 and create an abnormal chromosome called the Philadelphia chromosome. This translocation produces a fusion protein that is encoded by both BCR and ABL, the gene at the chromosome 9 breakpoint. If the translocation occurs in cells within the marrow bone, the fusion protein signals the body to make too many white blood cells which results in chronic myelogenous leukemia. The function of the normal BCR protein is still unclear.
The NF2 gene encodes the protein schwannomin (also known as merlin). This protein is produced in Schwann cells (cells which surround and insulate nerve cells), meningeal cells, lenses and nerves. Mutations in the NF2 gene are associated with neurofibromatosis type II. This inherited disease is characterized by tumors in the nervous system and skin, and abnormalities of the eyes.
The chromosome 22 image
The whole chromosome 22 image has a width of 3500 px and a height of 14214 px. It is too big to display here but you can download the chromosome 22 image. A 200 px wide overview of the chromosome can be seen on the right (bottom). Additionally, we show some details out of the original sized chromosome picture below.