Mutations occurring in the body lead to the formation of certain deviations. Depending on in which cells and at what stage they occur, hereditary variation may occur, i.e. such changes that are transmitted by inheritance to subsequent cells. Changes are made to certain signs of the body, depending on the genotype. They can persist for several generations, and in some cases there is an accumulation of such deviations.
Hereditary variability can be expressed in specific transformations that are serious enough to be immediately identified. The albinism of the body is an example of mutations and hereditary changes, this also includes the absence of plumage or horns in domestic animals and other similar signs. In vegetation, a similar phenomenon also happens - deviations in the size of the petals or plant height, and other obvious deviations from the norm. All this is a consequence of mutations and is included in the concept of hereditary changes in the body.
Formation mechanisms
In any group of individuals coexisting for a certain period of time, spontaneous mutations are formed . They are combined randomly based on existing inherited traits. The more deviations, the greater the likelihood of new changes that further deviate from the norm.
Mutations occur during cell formation. At the stage of gamete fusion, gene recombination occurs , which is the main cause of variability. The reason may be a divergence of chromosomes or their accidental combination during meiosis or fertilization. Due to the manifestation at such an early stage, hereditary variability is formed.
However, mutations do not occur spontaneously or accidentally, they are caused by exposure to certain factors. Mutagen can be radiation exposure, biological or viral exposure, chemicals.
If the cell in which the mutation occurred retains the ability to reproduce itself, then hereditary variation is most likely to form. Changes can be genetic, genomic, or chromosomal, depending on where they occur.
Mutations in evolution
Hereditary variation during evolution has had a marked effect on organisms. Its value is quite large, and for the first time this phenomenon and its mechanisms began to be studied back in the 18th century.
Charles Darwin said that every organism is subject to individual variability. Its main characteristics, he called randomness, relative rarity and non-directional nature. This markedly complicated the attempts to predict the process or any forecasts.
However, mutations also led to the formation of a reserve of hereditary variation, the formation of various genotypes. Nevertheless, in nature, this function is mainly performed by combinational variability - during sexual reproduction , recombination of chromosomes occurs. As a result, the compatibility of genes and their interaction in the genotype change, but the genes themselves do not change, therefore, deviations from the norm do not occur.
These processes help to better understand how modification and hereditary variation occurs. From the point of view of evolution, individual differences matter. When it comes to the manifestation of hereditary changes, not only the presence of abnormal genes is taken into account, but also their combination with other genes that are part of the genotype, in addition, environmental conditions and the direct development of the body can one way or another.
On the one hand, it is the exact transfer of gene material from one generation to another that is important, but, on the other hand, the conservation of information contained in genes can be extremely harmful to the body.