Drift of genes: the main regularities of this process

The DNA site on which a particular gene is located is called the locus. It may contain alternative variants of genetic information - alleles. In any population there is a large number of these structures. The share of a particular allele in the general genome of the population is called the frequency of the gene.

In order for a certain mutation to lead to evolutionary changes in species, its frequency must be high enough, and the mutant allele must be fixed in all individuals of each generation. With its insignificant amount, mutational changes can not affect the evolutionary history of organisms.

In order for the allele frequency to grow, certain factors must act-gene drift, migration, and natural selection.

Drift of genes is a random growth of an allele under the influence of several events that are combined and have a stochastic character. This process is associated with the fact that not all individuals in the population participate in reproduction. It is most typical for signs or diseases that are rare, but due to the lack of selection they are able to be stored in the genus or even a whole population of small size for a long time. This pattern is often traced in a small population, the number of which does not exceed 1000 individuals, since in this case migration is extremely small.

In order to better understand the drift of genes, one should know the following patterns. In cases where the allele frequency is 0, in subsequent generations it does not change. If it reaches 1, then it is said that the gene in the population is fixed. The random drift of the genes is the consequence of the fixation process with the simultaneous loss of one allele. Most often, this pattern is traced when mutations and migrations do not cause a permanent change in the constituent loci.

Since the frequency of genes is not directional, it reduces the diversity of species, and also increases the differences between local populations. It should be noted that this is counteracted by migration, in which different groups of organisms exchange their alleles. It should also be said that the drift of genes practically does not affect the frequency of individual genes in large populations, but in small groups it can become a decisive evolutionary factor. The number of alleles changes dramatically. Some genes can be irretrievably lost, which greatly impoverishes genetic diversity.

As an example, we can cite mass epidemics, after which the restoration of the population was carried out practically at the expense of several of its representatives. In this case, all descendants had an identical ancestral gene. In the future, the expansion of the allelic diversity was ensured by the importation of producers or by outreaches that contributed to the growth of differences at the gene level.

The extreme manifestation of the drift of genes can be called the emergence of a completely new population, which is formed only from a few individuals - the so-called effect of the founder.

It should be noted that biotechnology studies the patterns of genome rearrangement. Genetic engineering is the technique of this science, which allows you to transfer hereditary information. In this case, the transfer of genes allows you to fight with the interspecies barrier, and also give the necessary properties to the organisms.