repetitive DNA
Quick Summary
Repetitive DNA is a significant component of eukaryotic genomes, differing from prokaryotic DNA. It includes sequences that are repeated thousands of times, often clustered near centromeres, and are not transcribed into proteins.12
There are several categories of repetitive DNA:
* Single copy DNA: Contains structural, protein-coding genes.
* Families of DNA: Genes that have copied themselves, appearing as tandem or dispersed repeats.
* Satellite DNA: Short nucleotide sequences repeated many times, frequently found near centromeres.2
* Microsatellite DNA: Tandem repeats of two nucleotide pairs dispersed throughout the genome.
* Minisatellite DNA (VNTRs): Blocks of longer repeats dispersed throughout the genome.2
Transposons, or "jumping genes," are another type of repetitive DNA that can move to different locations within a genome. They can move via a "cut and paste" mechanism (Class II) or a "copy and paste" mechanism (retrotransposons). While often referred to as "junk DNA," transposons can sometimes cause genetic mutations or rearrangements that lead to disease. The exact function of much repetitive DNA, including satellite DNA, remains unknown.32
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