Skip to main content
Select Source:

selfish DNA

selfish DNA One of a number of hypotheses advanced in an attempt to explain the presence of surplus DNA in the genome which is not translated into protein. Three hypotheses have been put forward to account for the adaptive advantage of this apparently redundant DNA: (a) that extra DNA separates the genes so as to increase the cross-over frequency (see CROSSING-OVER); (b) that the possibility of varying the total amount of DNA per cell allows the control of cell volume and cell growth rate; and (c) (the selfish DNA hypothesis) that selection acts within the genome, favouring any method by which DNA may more rapidly replicate itself, and that this can be better achieved if phenotypic expression can be bypassed. This is achieved, it is proposed, by DNA spreading laterally so as to be duplicated at new loci elsewhere in the genome. In this way the DNA may be viewed as acting ‘selfishly’, since the apparently surplus DNA confers no advantage on the organism bearing it and therefore supplying the materials from which it is made. See also SELFISH GENES.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish DNA." A Dictionary of Zoology. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish DNA." A Dictionary of Zoology. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-1

"selfish DNA." A Dictionary of Zoology. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-1

selfish DNA

selfish DNA One of a number of hypotheses advanced in an attempt to explain the presence of surplus DNA in the genome which is not translated into protein. Three hypotheses have been put forward to account for the adaptive advantage of this apparently redundant DNA:
a. that extra DNA separates the genes so as to increase the cross-over frequency;

b. that the possibility of varying the total amount of DNA per cell allows the control of cell volume and cell growth rate; and

c. the selfish DNA hypothesis) that selection acts within the genome favouring any method by which DNA may more rapidly replicate itself, and that this can be better achieved if phenotypic expression can be bypassed.
This is achieved, it is proposed, by DNA spreading laterally so as to be duplicated at new loci elsewhere in the genome. In this way the DNA may be viewed as acting ‘selfishly’, since the apparently surplus DNA confers no advantage on the organism bearing it and therefore supplying the materials from which it is made. See also SELFISH GENES.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish DNA." A Dictionary of Plant Sciences. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish DNA." A Dictionary of Plant Sciences. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-0

"selfish DNA." A Dictionary of Plant Sciences. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-0

selfish DNA

selfish DNA Regions of DNA that apparently have no function (it is also known as ‘junk’ DNA) and exist between those regions of DNA that represent the genes. Transposons are good examples; certain types of repetitive DNA also have ‘selfish’ characteristics. Selfish DNA is so called as it seemingly exists only to pass copies of itself from one generation to another; it does so by acting like a ‘molecular parasite’, using the organism in which it is contained as a survival machine. This is known as the selfish DNA theory. The greatest amounts of selfish DNA are found in vertebrates and higher plants. The presence of selfish DNA may be due to an unrecognizable function that it performs or because the cell has no way of halting its increase in the genome.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish DNA." A Dictionary of Biology. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish DNA." A Dictionary of Biology. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-2

"selfish DNA." A Dictionary of Biology. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna-2

selfish genes

selfish genes A term used by some authors (most notably Richard Dawkins) to reinforce their notion that organisms function as agents for the replication of genes, as opposed to genes functioning as servants of organisms (i.e. that natural selection operates at the level of the gene). Opponents argue that natural selection operates at the level of the individual, not the gene, since it is the genome that survives or dies, not individual genes. See also SELFISH DNA.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish genes." A Dictionary of Plant Sciences. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish genes." A Dictionary of Plant Sciences. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-genes

"selfish genes." A Dictionary of Plant Sciences. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-genes

selfish genes

selfish genes Epithet used by some authors to reinforce their notion that organisms function as agents for replication of genes, as opposed to genes functioning as servants of organisms. See also SELFISH DNA.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish genes." A Dictionary of Zoology. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish genes." A Dictionary of Zoology. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-genes-0

"selfish genes." A Dictionary of Zoology. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-genes-0

selfish DNA

selfish DNA A segment of DNA which reproduces itself, but conveys no advantage to the genome in which it resides. Transposons are thought to be examples of selfish DNA.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"selfish DNA." A Dictionary of Ecology. . Encyclopedia.com. 18 Nov. 2017 <http://www.encyclopedia.com>.

"selfish DNA." A Dictionary of Ecology. . Encyclopedia.com. (November 18, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna

"selfish DNA." A Dictionary of Ecology. . Retrieved November 18, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/selfish-dna