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Repetitive DNA

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Definition

noun

(molecular biology) Repetitive nucleotide sequences in the DNA throughout the genome


Supplement

The repetitive DNA is a form of repeated sequences that, as the name implies, involves the DNA. It was originally identified by the C0t_ value derived from kinetic studies of DNA renaturation. The repeated sequences occur as multiple copies of nucleic acids in the genome. These repeats may occur in the DNA and the RNA. In repetitive DNA, 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

One class of repetitive DNA, termed highly repetitive DNA, is found as short sequences, 5-100 nucleotides, repeated thousands of times in a single long stretch. It typically comprises 3-10% of the genomic DNA and is predominantly satellite DNA. Another class, which comprises 25-40% of the DNA and termed moderately repetitive DNA, usually consists of sequences about 150 to 300 nucleotides in length dispersed evenly throughout the genome and includes alu sequences and transposons.


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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.