Mutation

MUTATION

  • Mutations are sudden heritable changes in a gene or chromosome, involving qualitative or quantitative alterations in the genetic material itself.
  • It produces an alteration in the character under its control.
  • The term mutation refers both to the changes in the genetic material and to the processes by which the change occurs.
  • The earliest record of point mutations dates back to 1791, when Seth Wright noticed a lamb with exceptionally short legs in his flock of sheep.
  • Visualizing the economic significance of this short-legged sheep, he produced a flock of sheep, each of which having short legs, by employing artificial breeding techniques.
  • The short legged breed of sheep was known as Ancon breed.
  • Hugo de Vries introduced the term "mutation" to describe the heritable phenotypic changes of the evening primrose, Oenothera lamarckiana.
  • The first scientific study of mutation was started in 1910, when Morgan started his work on fruitfly, Drosophila melanogaster and reported white eyed male individuals among red eyed male individuals.
  • The discovery of white eyed mutants in Drosophila is followed by an extensive search of other mutants of Drosophila by Morgan and his co-workers and other geneticists.
  • Consequently about 500 mutants of Drosophila have been reported by geneticists all over the world.
  • Later on, several cases of mutations have been reported in a variety of micro-organisms, plants and animals.

Mutant

  • The rate of mutation is increased either by using physical or chemical agents and this process is called as Mutagenesis .
  • An agent that has the ability to produce mutation is called the Mutagen .
  • The mutability of some genes is influenced by other genes called Mutator genes .

Mutation classification

Beneficial Mutations

  • Most mutations make the organism less efficient and are thus disadvantageous.
  • But mutations are invaluable for the process of evolution.
  • Plant breeders have reported that induced mutation can be used for improving grains and vegetables.
  • Barley mutant, for example have been obtained that provide increased yield.
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Last modified: Tuesday, 20 March 2012, 6:57 AM