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 ?
Some bits of "junk DNA," known as PATCs, may help by keeping the worms' own genes active in places where alien genes are turned off.
Second, although current technology permits law enforcement to use an arrestee's "junk" DNA only for identification purposes, (231) law enforcement can use junk DNA to perform "partial match searches." (232) The FBI currently uses these thirteen loci to perform partial match searches of its DNA databases, which are called "familial searches." (233) These searches permit partial matches.
The ENCODE research revealed that parts of the genome often dismissed in the past as "junk DNA" actually play an important role in regulating what genes do.
ROCK/POP Barfly, Kingsway, Cardiff Moments From Landing, Raphaelites, Junk DNA, 7.30pm.
Some stereotypes do turn up, like the zealous nun, Sister Chastity, the seductive astrobiologist, Oparna Goshmaulik, and the absent- minded Acharya -- he forgets his wife in the car and advances hypotheses on junk DNA as post- coital chatter with his mistress, Oparna.
Flash forward to a man floundering on stage going 'I thought there was more in this junk DNA routine...' "My life is like constant revision," he says.
The postulate G-SAT for short states that "Junk DNA IS the archive in which all the past and future history of life is preserved."
Previously, these non-coding sectors of the genome were termed "junk DNA," both because they could not be read and because it was believed they had no message for a would-be reader.
Much of our junk DNA consists of repetitive sequences and bits of viruses, legacies of infections that our ancestors survived.
Against the trendy opinion which takes fossil record as crucial for unearthing life's history, Ruse's emphasis is on other mutually consistent methods for reconstructing evolution's path and duration: radioactive dating, comparative studies of physical traits of organisms, or calculating the mutation rates of DNA molecules (especially of the 'junk DNA').
(18) Although an entire DNA molecule can provide extensive personal genetic information, these specific loci are allegedly void of such information, thereby warranting the title "junk DNA." (19) Debate exists, however, as to the legitimacy of that characterization.