Selfish DNA

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Selfish DNA (also known as parasitic DNA ) describes DNA sequences that are of no ostensible use for their host and that spread through the host's genome by inserting additional copies of themselves. They are therefore considered parasitic . Often, selfish DNA does not affect the host's phenotype . It can occur in the form of mobile genetic elements , but also as B chromosomes .

properties

The term was first used in 1976 by Richard Dawkins in his book The Selfish Gene , and the definition was subsequently adapted. Selfish DNA was originally thought to be a form of non-coding nucleic acids , but mostly has some protein- coding sequences that are used to replicate and translocate their DNA sequence, e.g. B. in inteins , homing endonucleases , insertion sequences , transposons , miniature inverted-repeat transposable elements , retro elements or B chromosomes. The MEDEA gene is a special form, which kills the mealworm offspring that do not carry it.

There may be a secondary function useful to the host in the form of an increased ability of the chromosomes contained in it to translocate and an increased genetic adaptability, e.g. B. in VDJ recombination . In addition, influences on the gene expression of other genes in the genome through regulation of the transcription of alternative promoters and through the generation of RNA interference were observed. As a result, there is a smooth transition from parasitism to symbiosis in some forms of self-serving DNA .

Artificial self-serving DNA is used, among other things, for gene drive .

Individual evidence

  1. ↑ Wolfram Hörz: Self-serving DNA: the parasite itself . In: News from chemistry, technology and the laboratory . tape 28 , no. 6 , June 1980, p. 387-388 , doi : 10.1002 / nadc.19800280608 .
  2. ^ Richard R. Dawkins : The Selfish Gene . Oxford University Press, New York 1976, ISBN 978-0-19-857519-1 .
  3. ^ WF Doolittle, C. Sapienza: Selfish genes, the phenotype paradigm and genome evolution . In: Nature . 284, No. 5757, 1980, pp. 601-603. doi : 10.1038 / 284601a0 . PMID 6245369 .
  4. ^ LE organ, Francis HC Crick : Selfish DNA: the ultimate parasite . In: Nature . 284, No. 5757, 1980, pp. 604-607. doi : 10.1038 / 284604a0 . PMID 7366731 .
  5. ^ SD Fugmann: The origins of the Rag genes - from transposition to V (D) J recombination. . In: Semin Immunol . 22, No. 1, 2010, pp. 10-16. doi : 10.1016 / j.smim.2009.11.004 . PMID 20004590 . PMC 2823946 (free full text).
  6. ↑ GJ Faulkner, PW Carninci: Altruistic functions for selfish DNA . (PDF) In: Cell Cycle . 8, No. 18, 2009, pp. 2895-2900. PMID 19736519 .