junk DNA


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junk DNA

that portion of DNA that is not transcribed and expressed, comprising a major fraction of the base pairs of the human genome; much of this DNA is repetitive in seuqence and appears to serve no purpose; its function is not known. segments of DNA that appear to serve no function and are replicated along with the rest of the DNA that serves vital functions; examples are pseudogenes and tandemly repeated DNA sequences that seem functionless but are retained by unequal crossing-over.
Synonym(s): selfish DNA

junk DNA

n.
A DNA sequence that is part of a genome and is not known to code for proteins or to regulate the expression of genes. Junk DNA may constitute up to 95 percent of the human genome and is postulated to be involved in the evolution of new genes and possibly the repair of genes.
Any long stretch of non-protein-coding DNA that composes 97–98% of the human genome, which has been highly conserved in plant and animal genomes over millions of years. It is now recognised that non-coding DNA determines the differences in transcription rates of genes, which is what makes each of us unique, making junk DNA is a misnomer

junk DNA

(jŭngk)
The portion of DNA that is not transcribed and expressed, comprising about 90% of the 3 billion base pairs of the human genome; its function is not known.
Synonym(s): selfish DNA.

junk DNA

The long sequences of DNA between those segments that code for protein. Only three percent of DNA consist of functional genes. The rest is junk DNA and is preserved over millions of years of evolution. Species differ not so much in the number of active genes as in the amount of junk DNA. These facts suggest the junk DNA has an important function, not yet discovered.

junk DNA

DNA of no apparent function, generally in GENOMES ofEUKARYOTES, where sequences have been repeated. Also called non-coding DNA.
References in periodicals archive ?
Third, while junk DNA currently identifies a particular human being, technological advances may permit more biological characteristics to be gleaned from the junk DNA.
SNPs can occur anywhere in the genome, both in our genes and in the so-called junk DNA.
Similar patterns of junk DNA in this gene are seen both in humans and bonobos - the chimpanzee subspecies known as the 'empathic ape'.
A great portion of organism genomes are composed of junk DNA that their cells must stop from transcribing.
THE growth of certain cancers may be triggered by junk DNA, say scientists.
Wayt Gibbs (2003) discusses junk DNA, saying, "Though long ago written off as irrelevant because they yield no proteins, many of these sections have been preserved mostly intact through millions of years of evolution.
I think what's going to happen in the next few years is that people are going to realize that there lies buried in that junk DNA, a whole heap of control and feedback mechanisms that regulate the expression of the genes," Mr.
For many years, they were considered junk DNA of no real use, a side-effect of our evolutionary journey.
The non-coding genome, previously referred to as junk DNA, makes up most of the human genome, and unlike the coding genome, varies greatly between species.
Furthermore, I believe that our proposed experiments to study retroelement biology in the AGS-context are likely to reveal truly exciting insights into the activity and control of junk DNA.
Within this junk DNA there are so-called called pseudogenes.
I have been using the following analogy ever since the junk DNA term entered the public literature: DNA strands are much like computer programs, which at the machine language level typically consist of long strings of "bytes," each consisting of eight "bits.