Hybridization (molecular biology)

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The hybridization ( lat. Hybrida: Mongrel, Bastard ; engl hybridisation.) Denotes a for molecular genetic important techniques operation in which on to a single strand of a DNA (eg. Southern blot or a) RNA (eg. Northern Blot ) a more or less completely complementary DNA or RNA single strand attaches by forming hydrogen bonds between the respective complementary nucleobases .

properties

The hybridization technique is used to demonstrate the structural relationship of nucleic acids and to isolate specific nucleic acid sequences from a mixture. The better the connecting DNA strands complement each other, i.e. the higher the proportion of correct complementary base pairings in the DNA hybrid, the higher the temperature ( melting temperature ) required for the separation into single strands , because more hydrogen bonds are formed due to the better base pairing than a hybrid with a lower proportion of correct base pairings. The temperature required to separate the hybridized DNA strands can be used to estimate how similar the complementary nucleotide sequences of the two DNA strands are. The rule of thumb here is that a deviation of 1 K (temperature unit Kelvin ) corresponds to around 1.3% of unpaired bases.

By marking with radioactive tracers or fluorescent dyes, enzymes and the like. a. shorter, usually artificially synthesized DNA chains can be used as gene probes by means of hybridization for the identification of corresponding nucleic acids. The DNA is often fixed by cross-linking . The hybridization technique is used in combination with other molecular genetic techniques, including as Southern blot , Northern blot or in the in situ method , e.g. B. on brain slices. The hybridization of primers in a polymerase chain reaction is called primer hybridization .

literature

  • Jeremy M. Berg, John L. Tymoczko, Lubert Stryer : Biochemistry. 6 edition, Spektrum Akademischer Verlag, Heidelberg 2007. ISBN 978-3-8274-1800-5 .
  • Donald Voet, Judith G. Voet: Biochemistry. 3rd edition, John Wiley & Sons, New York 2004. ISBN 0-471-19350-X .
  • Bruce Alberts , Alexander Johnson, Peter Walter, Julian Lewis, Martin Raff, Keith Roberts: Molecular Biology of the Cell , 5th Edition, Taylor & Francis 2007, ISBN 978-0815341062 .