Directed mutagenesis

Directed mutagenesis, also known as directed mutation, is a hypothesis proposing that organisms can respond to environmental stresses through directing mutations to certain genes or areas of the genome.

The hypothesis was first proposed in 1988 [1] by John Cairns, of Harvard University,[citation needed] who was studying Escherichia coli that lacked the ability to metabolize lactose. He grew these bacteria in media in which lactose was the only source of energy. In doing so, he found that the rate at which the bacteria evolved the ability to metabolize lactose was many orders of magnitude higher than would be expected if the mutations were truly random. This inspired him to propose that the mutations that had occurred had been directed at those genes involved in lactose utilization.[2][3]

Later support for this hypothesis came from Susan Rosenberg, then at the University of Alberta, who found that an enzyme involved in DNA recombinational repair, recBCD, was necessary for the directed mutagenesis observed by Cairns and colleagues in 1989.

The directed mutagenesis hypothesis was challenged in 2002, when John Roth and colleagues showed that the phenomenon was due to general hypermutability due to selected gene amplification, and was thus a "standard Darwinian process." Later research published in 2006 by Jeffrey D. Stumpf, Anthony R. Poteete, and Patricia L. Foster, however, concluded that amplification could not account for the adaptive mutation and that "mutants that appear during the first few days of lactose selection are true revertants that arise in a single step".

References

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Look at other dictionaries:

  • directed mutagenesis — directed mutagenesis. = site specific mutagenesis (см.). (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • directed mutagenesis — directed mutagenesis. См. направленный мутагенез. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • directed mutagenesis — The generation of changes in the nucleotide sequence of a cloned gene by one of several procedures. Undertaken to explore the relationship between nucleotide sequence and gene function, and to modify gene products. Synonym: in vitro mutagenesis …   Glossary of Biotechnology

  • Site-directed mutagenesis — Site directed mutagenesis, also called site specific mutagenesis or oligonucleotide directed mutagenesis, is a molecular biology technique in which a mutation is created at a defined site in a DNA molecule. In general, this form of mutagenesis… …   Wikipedia

  • oligonucleotide-directed mutagenesis — oligonucleotide directed mutagenesis. = site specified mutagenesis (см.). (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • site-directed mutagenesis — site directed mutagenesis. См. направленный мутагенез. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • oligonucleotide-directed mutagenesis — oligonucleotide directed mutagenesis. См. сайт специфический мутагенез. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • site-directed mutagenesis — See site specific mutagenesis …   Dictionary of molecular biology

  • site-directed mutagenesis — site specific mutagenesis a method for producing a defined DNA mutation; a sequence alteration is made in vitro at a specific nucleotide or region and the altered DNA is reintroduced into cells …   Medical dictionary

  • oligonucleotide-directed mutagenesis — See: site specific mutagenesis …   Glossary of Biotechnology

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