Dictionary > Retrotransposon

Retrotransposon

Definition
noun, plural: retrotransposons
A transposon that is amplified via reverse transcription, i.e. the DNA element is first transcribed into RNA and reverse-transcribed into DNA, and then inserted elsewhere of the genome
Supplement
Transposable elements or transposons are small DNA segments capable of replicating and inserting copies of DNA at random sites in the same or a different chromosome. Thus, they are mobile and capable of producing changes in the genome of an organism. In eukaryotes, transposons may be classified as Class I or Class II. A retrotransposon is a Class I transposon. It amplifies by first undergoing reverse transcription. Initially, the DNA element is transcribed into RNA. The RNA is then reverse-transcribed into DNA. The DNA copy is then inserted back to the genome but at a different position. The amplification of genetic material is similar to retroviruses. The need for RNA intermediate makes retrotransposons different from DNA transposons that belong to Class II transposons.
Retrotransposons are common in plants and serve as the major component of the nuclear DNA. For instance, the genome of maize is comprised of 49 to 78 % retrotransposons.1 They also occur in animals and humans. In humans, the genome consists of around 42 % retrotransposons.2
Retrotransposons may be classified into three groups: (1) transposons with long terminal repeats, (2) long interspersed nuclear elements, and (3) short interspersed nuclear elements.
See also:

Reference(s):

1 SanMiguel, P. & Bennetzen, J. L. (1998). “Evidence that a recent increase in maize genome size was caused by the massive amplification of intergene retrotranposons”. Annals of Botany 82 (Suppl 1): 37–44.

2 Lander, E. S., Linton, L. M., Birren, B., et al. (2001). “Initial sequencing and analysis of the human genome”. Nature 409 (6822): 860–921.


You will also like...

Early Earth
The Origins of Life

This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..

Still freshwater and plants
Still Freshwater & Plants

Plants in lentic habitats have features not found in terrestrial plants. They acquired these features as they adapt to t..

Still Water Community Plants
Still Water Community Plants

This tutorial looks at the adaptations of freshwater plants for them to thrive in still water habitats. Familiarize your..

Growth Patterns
Growth Patterns

This tutorial describes the sigmoid curve, annual plant growth, tree growth, human growth, and insect growth as the grow..

Birth Control and Contraception
Birth Control and Contraception

Different pregnancy and birth control and contraception strategies are described. Read this tutorial to learn each of th..

Homeostasis by water regulation
Homeostasis of Organism Water Regulation

Osmoregulation is the regulation of water concentrations in the bloodstream, effectively controlling the amount of water..