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• junk DNA
  junk DNA

  segments of DNA that have no apparent genetic function.
• “junk” DNA
  “junk” DNA

  Segments of DNA along a chromosome that are not genes, do not code for anything that we know of, and whose purpose we do not understand. Approximately ninety-five percent of the human genome falls into this category. The term junk may be misleading, however, as this DNA may have other functions, such as regulating genes during development.

junk DNA

American  

1. segments of DNA that have no apparent genetic function.

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junk DNA British  

noun

1. DNA that consists of repeated sequences of nucleotide and has no apparent function

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junk DNA Scientific  

/ jŭngk /

1. DNA that serves no known biological purpose, such as coding for proteins or their regulation. Junk DNA makes up the vast majority of the DNA in the cells of most plants and animals, composing, for example, about 95 percent of the human genome.

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“junk” DNA Cultural  

1. Segments of DNA along a chromosome that are not genes, do not code for anything that we know of, and whose purpose we do not understand. Approximately ninety-five percent of the human genome falls into this category. The term junk may be misleading, however, as this DNA may have other functions, such as regulating genes during development.

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Discover More

Some scientists speculate that junk DNA may be archaic material left over from an earlier stage of evolutionary development.

Etymology

Origin of junk DNA

1990–95

Example Sentences

Long considered "junk DNA," these non-coding sequences are now recognized to play a crucial role in controlling which genes get expressed in a cell and when.

From Science Daily • Dec. 13, 2023

Further research is needed, however, to confirm that this mechanism also happens in humans and to figure out how junk DNA sequences are able to hijack H2A.Z.

From Science Daily • Nov. 16, 2023

Transposons are indeed junk DNA, says Ting Wang, a genomic scientist who studies transposons at the Washington University School of Medicine in St. Louis.

From Scientific American • Feb. 2, 2022

Spontaneous fluctuations are like the dark matter or "junk" DNA of the brain.

From Salon • Aug. 28, 2021

But to counteract this, the Welwitschia genome underwent widespread epigenetic changes that silenced these junk DNA sequences, through a process called DNA methylation.

From New York Times • Jul. 31, 2021