All about mutations. Evolutionary role

Mutation is called persistent changes in the genotype that occur due to the influence of external and internal factors. The ancestor of the term is Hugo de Vries-Dutch botanist and geneticist. The process, when the mutation is called mutagenesis. In today's article we will touch the topic of mutation and talk about the role of mutations in evolution.

Cause

The Process of mutation is characterized by two qualities-spontaneity and inducing. The emergence of a spontaneous mutation characterized by spontaneity and is found at any stage of development of the organism. With regard to the environment, it should be natural.

Induced type of mutation is an inherited change in the genome that occurs as a result of exposure to different mutagens. Organisms are placed either in artificial (experimental) or unfavorable ambient conditions.

Living cells perceive mutagenesis as a natural process. The main processes responsible for the mutation include: replication and disturbance of DNA repair, transcription process and genetic recombination.

Mutagenesis and the model

In explaining and understanding the nature and mechanisms of appearance of the mutations help the special scientific approaches. Polymerase changes are based on the theory of direct and sole dependence of the mutation with the errors of a DNA polymer. In catumiri models of mutagenesis, invited two well-known biologists, was first touched upon the idea that the bulk of mutations is the ability of DNA bases to be in different catumiri forms.

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Early classification of mutations

Geneticist Meller was the classification of mutations based on the types of changes in the functioning of genes. As a result the following types:

1. Amorphous. During mutation, the gene loses almost all of its functions. Example mutations include changes in Drosophila.
2. Hypomorphic. Changed alleles continue to operate under the same scenario, and wild. The synthesis of the protein product is carried out in smaller amounts.
3. Antimony. The change of the mutant trait. Examples of mutation have become some of the corn - colored brown colour, and not purple.
4. Neomorphic.

Late classification of mutations

In the modern scientific references, there is mention of formal classification, which starts from the changes that occur in different structures. Based on this division, there are the following mutations:

1. Genome.
2. Chromosome.
3. Gene.

The genomic mutations associated changes of chromosomes, total number of which is not correlated with the halide set.

Chromosomal mutations attributed to the restructuring of certain chromosomes in large numbers. The genetic material in this case, losing a part, or, conversely, doubles it.

As for genetic mutation, it only slightly modifies the DNA structure of a gene, unlike other species, however its occurrence happens more often.

In the gene of a species is allocated one subspecies, called a point mutation. It is one nitrogenous base is replaced by another.

The Evolutionary role of mutations

Sometimes it Happens that the harmfulness of mutations gradually replaced by the utility. The impetus for such change has become ever-changing conditions of existence of organisms. So what is the role of mutation?

Take the example of natural selection — the evolutionary process is largely dependent on the variability. Consider the evolutionary role of mutations, for example, mutant melanistic (individuals with a dark color), which was discovered by English scientists of the 14th century in the study birch of moths. In addition to butterflies, painted in typical bright colors were found and other individuals, whose color was much darker. The reason for such strong differences became mutated gene.

The fact that the usual habitat for these butterflies are the trees, the trunks of which the lichen grows abundantly. Prevailed in the early years of the industrial revolution together with a strong pollution layers led to the death of lichens. Once the light guns appeared soot, which interfere with the natural disguise of the birch moth. All this has led to the fact that individuals, whose habitat was industrial areas, change the color of their morph from light to dark. Such evolutionary role of mutation helped to survive many butterflies, while they are not a very good light relatives were victims of the attacks of birds of prey.

Similar changes occur in the most diverse types worldwide. The appearance of these useful traits, which is the basis of the evolutionary role of mutations, leads to the fact that natural selection gave rise to new subspecies and species among living organisms. The mutation happens all the time, because it is the natural ability of our genes.

More information about the mutations you find in textbooks of biology and special scientific literature.