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Chromosome 22

Chromosome 22

What is chromosome 22?

Chromosome 22 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 22 is the second smallest human chromosome, spanning about 49 million base pairs (the building material of DNA) and representing between 1.5 and 2 percent of the total DNA in cells.

In 1999, researchers working on the Human Genome Project announced that they had determined the sequence of base pairs that make up this chromosome. Chromosome 22 was the first human chromosome to be fully sequenced.

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 22 likely contains between 500 and 800 genes.

Genes on chromosome 22 are among the estimated 30,000 to 40,000 total genes in the human genome.

There are many conditions related to genes on chromosome 22.

Is there a standard way to diagram chromosome 22?

Geneticists use diagrams called ideograms as a standard representation for chromosomes. Ideograms show a chromosome's relative size and its banding pattern. A banding pattern is the characteristic pattern of dark and light bands that appears when a chromosome is stained with a chemical solution and then viewed under a microscope. These bands are used to describe the location of genes on each chromosome.

Where can I find information about chromosome 22?

You may find the following resources about chromosome 22 helpful.

You may also be interested in these resources, which are designed for genetics professionals.

Where can I find general information about chromosomes?

The Handbook provides basic information about genetics in clear language.

What glossary definitions help with understanding chromosome 22?

base pair ; chromosome ; DNA ; gene ; genome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

 
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The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.
 
Updated: July 22, 2004
Published: October 8, 2004
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