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 ?
It also provided new evidence that mutations in the non-coding DNA may cause cancer by altering the 3-dimensional (3D) genome structure.
7,2011, 4:03 PM), http://www.pbs.org/newshour/rundown/2011/11/j unk-dna.html (stating that although non-coding DNA was believed to be nonfunctional, some modern researchers are finding that these unexplored regions of DNA may play important roles); New Findings Challenge Established Views on Human Genome, Nat'l Human Genome RESEARCH INST., http://www.genome.gov/25521554 (last updated July 7, 2011).
These would also have emerged from non-coding DNA over the past five or six million years.
Genetic Technologies granted a limited license to Nanogen for the use of its non-coding DNA analysis patents ...
The genomic copies of some genes in the germline micronucleus of hypotrichous ciliates are crippled by the presence of intervening non-coding DNA sequence elements (internally eliminated sequences, or IESs) which must be removed before a functional copy can be assembled in the somatic macronucleus.
Using its gene control platform, Syros discovered subsets of AML and MDS patients whose tumors have a highly specialised regulatory region of non-coding DNA, known as a super-enhancer, that is associated with the RARA gene, which codes for the RAR?
Researchers can now identify DNA regions within non-coding DNA, the major part of the genome that is not translated into a protein, where mutations can cause diseases such as cancer.
Using the latest gene sequencing techniques and sophisticated computer analysis, a research group led by Professor John Rasko AO and including Centenary's Head of Bioinformatics, Dr William Ritchie, has shown how particular white blood cells use non-coding DNA to regulate the activity of a group of genes that determines their shape and function.
In fact, organisms simpler than roundworms, such as single-celled bacteria, carry little non-coding DNA and may have no regulatory RNA at all.
Cationic lipids are formulated with non-coding DNA (plasmid) to create JuvImmune(TM), a single lipid-DNA complex, which as an immunostimulation product will have utility in a number of non-antigen immunotherapeutic applications.

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