Jump To:

• 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.

---

junk DNA British  

noun

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

---

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.

---

“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.

---

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

See Examples For:

junk DNA “junk” DNA

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

Non-coding variants were once thought to be "junk DNA" by scientists.

From Science Daily ● Sep. 22, 2023

Once that happens, they lead to the creation of what is colloquially known as "junk DNA," or genetic material in our genome for which there is no known purpose.

From Salon ● Dec. 6, 2022

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

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

The bladderwort’s time in the spotlight was thanks to the discovery that it is nearly free of non-protein coding “junk” DNA, a material nearly every other complex organism is awash in, including you.

From Scientific American ● May 19, 2013

I was startled to learn recently that geneticists now refer to the 80 percent of the human genome that does not code for genes — once called “junk” DNA — as biological dark matter.

From New York Times ● Sep. 24, 2012

Let’s tackle “junk” DNA first, a term I find as ugly and misleading as the word “slush” for responses to open submission calls.

From Scientific American ● Sep. 17, 2012