Extrachromosomal DNA

Extrachromosomal DNA is a type of DNA that is not located within the chromosomes. Instead, it is found outside of the chromosomes in the cytoplasm or nucleus. This DNA can be found in various forms such as plasmids, mitochondrial DNA, and chloroplast DNA.

Overview

Extrachromosomal DNA is a significant part of the genetic material in a cell. It is not bound by the same restrictions as chromosomal DNA, allowing it to replicate independently and often at a faster rate. This can lead to an increase in the number of copies of certain genes, which can have various effects on the organism.

Types of Extrachromosomal DNA

Plasmids

Plasmids are small, circular pieces of DNA that are found in bacteria and some eukaryotes. They can replicate independently of the chromosomal DNA and can be transferred between cells. Plasmids often carry genes that provide a survival advantage to the organism, such as antibiotic resistance genes.

Mitochondrial DNA

Mitochondrial DNA (mtDNA) is found in the mitochondria, the energy-producing organelles in the cell. Unlike chromosomal DNA, mtDNA is inherited solely from the mother. Mutations in mtDNA can lead to various diseases, including Leber's hereditary optic neuropathy and mitochondrial myopathy.

Chloroplast DNA

Chloroplast DNA (cpDNA) is found in the chloroplasts of plants and algae. Like mtDNA, cpDNA is inherited from the mother. It is responsible for photosynthesis and other functions of the chloroplast.

Role in Disease

Extrachromosomal DNA can play a role in disease. For example, certain cancers have been found to have high levels of extrachromosomal DNA, which can lead to an increase in the number of copies of oncogenes. This can drive the growth and spread of the cancer.

See Also

• DNA
• Chromosomes
• Plasmids
• Mitochondrial DNA
• Chloroplast DNA

This article is a medical stub. You can help WikiMD by expanding it!
Most recent articles Ongoing trials	Wikipedia

• 

  PBR322 plasmid showing restriction sites and resistance genes

• 

  Map of the human mitochondrial genome

• 

  Mitochondrial inheritance