Mutation

of these articles concerns itself with the biological meaning of the word mutation. The grammatical meaning is treated under Anlautmutationen, the pressure-technical under mutation (media).

A mutation (lat. courage acres change) are a change of the hereditary property of an organism throughChange of the succession of the Nucleotidbausteine or by change of the Chromosomenzahl, which are not based on recombination or segregation. This term is used therefore only for a subrange of all possible Chromosomenaberrationen. By a mutation into the DNA stored information one changesand thus individual characteristics (the phenotype) can be changed.

Table of contents

kinds of the mutation

distinction after heritability

  • germ course mutations
    are mutations, which are passed on to the descendants over the germ course; itconcern Eizellen or sperm cellses and by cell division to all other cells are passed on. These mutations are very important in the context of the evolution theory, since they are transferable to the next from a generation.
  • somatic mutations
    are mutations, the all other body cells howeverthe germ cells to concern cannot. They have therefore also only effects on the cells of the organism, in which they take place, i.e. somatic mutations are not left. If these somatic mutations arise only isolated, they do not have or only small consequences.Becomes their occurrence however by Mutagene like e.g. radiation high-energy or environmental poisons strengthened, has it a large danger potential. So can itself thereby among other things normal body cells into without brakes rampantly growing cancer cells convert. Also with the aging process of each organism somatic mutations playa crucial role. They have therefore in the practical medicine an increasing meaning.

distinction according to a cause

  • spontaneous mutations
    are mutations without a recognizable cause, like the chemical decay of a nucleotide (cytosine oxidative e.g. desaminiert. spontaneously to uracil).
  • induced mutations
    are by Mutagene (mutation-releasing materials or radiations) produced mutations.
  • Replikationsfehler
    DNA polymerases have differently high error rates. Preferred a ATP is inserted, since the molecule occurs most frequently in the cell.
  • Insufficient Proof reading activity
    some DNA polymerases have the possibility falseinsert independentlyto recognize and correct. The DNA polymerase α the Eukaryoten however e.g. possesses. no proof reading activity.
  • Error with prä and postreplikativen repair mechanisms
    with the installation/finding an unusual nucleotide, approximately of uracil in the DNA, is removed this, during a false mating between 2DNA typical nucleotides must the Repraturenzym decide with 50%iger error probability.
  • Integration or jumping out Transposons
    jumping elements can integrate in genes or genregulatorische ranges. When jumping out they leave, so-called to traces footprints.

distinction after change

  • 1. the Genmutation
    a hereditary change, which concerns only the individual gene. One differentiates between raster and point mutation.With the point mutation an organic cousin in the genetic code is only changed (mutated). The raster mutation however leads to the module or removing of a cousin and changes thus the entire structure of the gene. Therefore the raster mutation has far higher effects.
  • 2. those Chromosomenmutation or segment mutation
    likewise a hereditary change, which concerns individual Chromosomen in its structure.

With the discovery of the alternative Splicings a further type of mutation is added: the changed regularization of the Splicings, which is embodied in the long run also in the hereditary property, but usually in other place. Same applies to mutations the Expression adjusting regionsin gene proximity.

distinction after consequences for the organism

  • lethal mutations
    are mutations, which kill an organism after their occurrence independently of its respective life phase in each case.
  • condition-aluminum-lethal mutations
    are mutations, their change of the gene product an organismonly with certain growth conditions kills.
  • loss OF function mutations
    here becomes a gene by a mutation functionless. If the function loss is complete, one speaks also of zero-allele or an amorphous allele. If a part of the function of type of game remains, then one designatesit also also as hypomorphes allele.
loss OF function mutations are always rezessiv, since another allele can catch the function loss of a gene.
  • gain OF function mutations
    here wins a gene at activity and becomes then also as hypermorphdesignated. If a completely new phenotype results from the mutation, then one calls the allele also neomorph.
One gain OF function mutation always produces a phenotype for dominant factors.
  • neutral mutations
    can change the phenotype, have however no Fitnesskonsequenzen.
  • quiet mutations
    are mutations, which do not have any consequences for the organism.

consequences

no consequences - with quiet, neutral mutations

most mutations lead to the fact that a change in a DNA - section no consequences afterpulls itself, if the place, which was changed, is used not for genetically relevant information. In addition, if the changed place is used, it can be that the information content of the gene did not change, there a set ofAmino acids are identically coded (see: genetic code). Therefore these mutations quiet mutations or neutral mutations are called.

Such kinds of mutations lead to the fact that within a group of organisms functionally same genes different genetic „letters “within their Nucleotide - sequence possess. These differences, which are called Polymorphismen, can be used, in order to derive family relations between individuals, or also, in order to measure an average mutation rate.

Additionally still it comes to carrying that not only with the diploiden Chromosomensatz often several genes the same geneticCharacteristics code, so that a mutation for this reason does not have immediately to become disadvantageful apparent.

negative consequences

particularly larger changes in the hereditary property often lead to disadvantageful changes in the metabolism or also to false formations and other characteristics.

Itgives different hereditary diseases, which are either left or can by mutation again occur. Examples of it are:

positive consequences

of the development teachings according to Darwins is the mutation also for the diversity of species on earth responsible. Mutations are like that (however not only) a natural phenomenon and make possible only the development of the kinds (see: Evolution teachings). Although the mutation constitutes the dynamics of the evolution, is only in the rarer cases alsoa change in the Genom an advantage for the individual to expect (more exactly 0.001% of all mutations are positive).

Proteins are changed or adjusted by exchange of the pairs of cousins simply only differently, which a change in the figure, or in bodily functions and or inBehavior of the organism to cause can, which offers advantages to it opposite its unchanged kind comrades. If this mutation is left to the descendants, it fulfilled a first condition that they intersperse themselves once „“can.

Humans make themselves besides the genomveränderndenEffect ionizing rays, in order to release mutations artificially. An application exists in the irradiation of flower and plant seeds, in order to produce and economically use unknown forms. The procedure has usually due to the breitgesteuten, to extensive and unaimed changethe hereditary material a very small success ratio.

normally

  • white wings with black design have examples of the Birkenspanner butterfly and are in such a way camouflaged on the Birkenrinde in relation to its enemies well. At the beginning of the industriellen revolution the Birken became inthe English industrial areas ever more russiger and the lightwhite Birkenspanner ever more rarely. After some time the Birkenspanner became however again more frequently, however now in a new Varietät with grey wings. Such mutation had also in former times already given it, it could do itselfbut interspersed only under the new environmental condition. This is an example of micro evolution.
    This well-known example is however very disputed. See in addition Industriemelanismus.
  • Manx cats resulted from Genmutation due to extreme in-breeding. Beside the Schwanzlosigkeit exist skeleton deformations and furtherFalse formations. Manx cats are in this mutated gene “M” never pure-bend, it are present thus with them the combination “mm”, i.e. there is a autosomal imperfectly dominanter hereditary course with variable Expressivität (development). With animals with the pure-curved gene combination “mm” die thoseFeten already in the nut/mother body.
  • The Sphynx cat does not have any skin. This race is further-bred since 1966 from, a naturally mutated cat born in Canada by humans. During the present legislation in all countries the desire for always new race attractions leads to it,that one continues to breed also animals, which would not be lebensfähig under natural conditions.
  • In the plant breeding mutations make large progress possible. From grasses with small seeds productive grain places were bred. Without plant breeding and mutations it would be not possible the population of world toonourish.
  • Laktose - tolerance with humans. It tightened Genetiker that humans originally generally with a genetically determined (embodied), only on the childness limited Laktosetoleranz (milk and/or. Lactose compatibility) was equipped. In opinion of the researchers must forwards approx. 10,000 years (afterother sources approx. 8,000 years) arisen with humans in the Caucasian area a mutation its, which expanded the Laktosetoleranz since the entire life-span. Thus all descendants do not show this humans time of its life health impairment with the consumption of milk,like it on the other hand this very day among other things with Asians or African arises, who were not affected by this mutation at that time and there also today is therefore not (see lactose intolerance).
  • Brain development of humans. The genes Microcephalin and ASPM steer with humansthe size growth of the brain and in particular that the brain cortex. Obviously the development of the human brain is not however by any means final. Researchers around Bruce Lahn of the Howard Hughes Medical of institutes of the University OF Chicago (the USA) found out that two mutations in thatrecent human master history for the brain made possible to adapt to the changed requirements better. The Haplogruppe D as result of a mutation of the Microcephalins developed before 37,000 years in the human Genom and spread about at the same time to the oldest finds, ofwitness to the occupation of humans with art, music and religion. One finds this mutation today with approximately 70% of all humans. With a further mutation the Haplogruppe D of the ASPM developed and spread about at the same time before about 5,800 yearsto the first civilization in Mesopotamien out, from which also the oldest writing finds of mankind history come. This second mutation became generally accepted until today with approximately 30% of the population of world. Both gene variants resulted from mutation come now to data of the researchers particularlyin Europe and the adjacent areas of Asia and Africa forwards. The parallelism of the described events from the scientists there it is interpreted going that due to positive selection the evolutionary success of the two mutations with their favorable influence on the developmentthe human brain and its efficiency in connection stands.

horticulture

in the horticulture is called a mutation, from which a new sort develops, also „modification “or „sport “.

 

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