Mobile genetic elements facts for kids
Mobile genetic elements (MGE) are special pieces of DNA that can move around inside a cell's genome. Think of them like tiny, movable puzzle pieces within a cell's instruction book. They can jump from one spot to another, or even make copies of themselves and insert those copies elsewhere.
These moving DNA pieces are found in almost all living things, from tiny bacteria to plants and animals. They play a big role in how evolution works and how new traits appear. The total collection of all mobile genetic elements in a genome is sometimes called the mobilome.
Contents
What Are Mobile Genetic Elements?
Mobile genetic elements are sections of DNA that have the ability to change their position within the genome. This movement can sometimes change how a cell works. They can also help spread genes, like those that make bacteria resistant to medicines.
Types of Mobile Genetic Elements
There are several different kinds of mobile genetic elements. Each type moves in a slightly different way:
Transposons
Transposons are also called "jumping genes." They are a major type of MGE. There are two main kinds:
- Retrotransposons: These work by making a copy of themselves using RNA (a molecule similar to DNA). This RNA copy is then turned back into DNA and inserted into a new spot in the genome.
- DNA transposons: These move directly from one place to another in the genome. They are cut out from their original spot and pasted into a new one.
Plasmids
Plasmids are small, circular pieces of DNA found mostly in bacteria. They are separate from the main bacterial chromosome. Plasmids can carry genes that give bacteria special abilities, like being resistant to antibiotics. They can also be easily shared between different bacteria.
Bacteriophage Elements
Some bacteriophages (viruses that infect bacteria) can insert their own DNA into a bacterium's genome. For example, the Mu phage is known for integrating its DNA randomly into the host's genome. This means the virus's genes become part of the bacterial cell's own DNA.
Group II Introns
Group II introns are special parts of RNA that can cut themselves out of a larger RNA molecule and sometimes insert themselves into DNA. They are found in many different organisms, including bacteria and in the DNA of mitochondria and chloroplasts (parts of cells that produce energy).
Discovery of Jumping Genes
The idea of mobile genetic elements was first discovered by a brilliant scientist named Barbara McClintock. She was studying corn plants in the 1940s and noticed that some genes seemed to move around. This caused changes in the corn's kernel colors.
At first, her ideas were very new and not widely accepted by other scientists. But over time, more research showed she was right. For her groundbreaking discovery of mobile genetic elements, Barbara McClintock was awarded the Nobel Prize in Physiology or Medicine in 1983. Her work changed how we understand genetics and how genomes can change over time.
Related pages
See also
In Spanish: Elementos genéticos móviles para niños
