Tell about a mutation as the phenomenon in recent years much. Generally this talk is connected with bad ecology, consequences of radiation and production of genetically modified products. But, according to scientists, all beings living on the earth to a degree mutants. Whether so it and what is a mutation?
The environment plays not the last role in formation of organisms. In spite of the fact that replication of DNA happens to phenomenal accuracy, from time to time there is a failure of the program, or a mutation. The cause of failure hereditary dysfunction of DNA this manifestation possible influence of the world around can be frequent, however. Chemical compounds, viruses, the ionizing radiation - here only some features of the environment which can cause a mutation. However the phenomenon of a mutation in itself is necessary for evolutionary development of a look, and the mankind in this sense is not an exception at all. In each new generation of people as scientists defined, appear a large number of individuals – carriers of mutational genes, however process of manifestation of mutations nevertheless is very rare. Ramps are these new models of genes which are created as a result of mutational transformations, create an evolutionary variety, serve for ensuring diversity of development of a genotype. Thus, a mutation as the phenomenon it is extremely important also for full development of a look in general.
Distinguish several types of mutations. Neutral mutations which identification is possible only in the gene analysis do not affect development of an organism in any way. At a neutral mutation in amino acid there is a replacement of nucleotides which are similar in essence and to functioning. Replacements of this sort are called synonymous. They do not influence work of codons units of the genetic code whose task is amino acid inclusion coding. For this reason such mutation is called neutral.
Not synonymic mutation usually is harmful. In case of such mutation there is influence on a codon owing to what there are deviations in development of the individual or even the whole look. However there is some very small possibility of positive influence of not synonymic mutation on an organism. Scientists call such phenomenon "a rare positive mutation". It must be kept in mind that all classification of mutations is sufficiently conditional and depends in many respects on in what conditions there is an activity of a concrete organism. Let's tell, some insects mutated and gained immunity to action to DDT and other insecticides before for the first time met their destructive impact on population. Therefore, at first their mutation was neutral, not influencing an organism and a way of activity. But after this mutation helped insects to survive with emergency conditions, it became useful. Supporters of the mutational theory of evolution consider mutations the phenomena accidental. At the same time highly appreciating "natural selection" whose functions assessment of mutational changes and suppression of development of harmful mutations of an organism enters. A special role in development of a separate look is played by such chromosomal and genomic mutations as a poliploidiya (increase in number of chromosomes) and duplications (changes of some sites of chromosomes). They create a certain genetic reserve of a look, providing to evolutionary process leeway, increasing quantity of genes with absolutely new properties.