Dictionary > Repeated sequences

Repeated sequences

Definition
noun
(molecular biology) Multiple copies of nucleotide sequences in the nucleic acids (i.e. DNA or RNA) throughout the genome
Supplement
The repeated sequences occur as multiple copies of nucleic acids in the genome. These repeats may involve the DNA or the RNA. In repetitive DNA, for instance, stretches of DNA repeats occur in the genome as either in tandem or interspersed along the genome. These repeats are found in various organisms. In humans, there may be over two-thirds of repetitive DNA in the genome.1
There are three major types of repeated sequences: (1) terminal repeats, (2) tandem repeats, and (3) interspersed repeats. The terminal repeats are repeated sequences that occur terminally, i.e. on both the 5′ and 3′ ends of a sequence. Tandem repeats are repeated sequences in which the copies lie adjacent to each other. These include satellite DNA, minisatellites and macrosatellites. Interspersed repeats (also called interspersed nuclear elements) are repeated sequences in which the copies are dispersed throughout the genome. Unlike tandem repeats, the interspersed repeats have copies that are nonadjacent. These include the transposable elements (transposons), such as DNA transposons and retrotransposons.
See also:

Reference(s):

1 de Koning A. P., Gu, W., Castoe, T. A., Batzer, M. A., & Pollock, D. D. (2011). “Repetitive elements may comprise over two-thirds of the human genome.” PLoS Genet., 7(12): e1002384.


You will also like...

Biological Cell Defense
Biological Cell Defense

Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..

Principles of Hormonal Control Systems
Principles of Hormonal Control Systems

Hormones are essential in the regulation of the activity of the various biological systems of the human body. The ineffi..

Regulation of Biological Systems
Regulation of Biological Systems

Regulation of Biological Systems tutorials are focused on the modulation of biological systems from cell to population l..

Pikas are an indicator species for climate change
Indicator Species and Endangered Species

Certain species are capable of expressing characteristics indicative of the state of the ecosystem they occupy. They are..

Golgi apparatus (3-D illustration)
Role of Golgi Apparatus & Endoplasmic Reticulum in Protein Synthesis

The endoplasmic reticulum and Golgi apparatus are the organelles involved in the translation step of protein synthesis a..

Kidneys
Kidneys and Regulation of Water and Inorganic Ions

The kidneys are responsible for the regulation of water and inorganic ions. Read this tutorial to learn about the differ..