region of DNA that is hosting a specific gene, called a locus.It may contain genetic information alternatives - alleles.In any population, there is a large amount of data structures.The share of a specific allele in the genome of the general population is called the frequency of the gene.
that certain mutations lead to evolutionary changes in species, its frequency should be sufficiently high, and the mutant allele should be fixed in all individuals of each generation.When small quantity mutational changes are not able to influence the evolutionary history of organisms.
To allele frequency grew to act certain factors - genetic drift, migration and natural selection.
Gene flow - a random allele growth when exposed to several events that combine and have a stochastic nature.This process is associated with the fact that not all individuals in the population are involved in reproduction.It is most typical symptoms or diseases which are rare, but due to the absence of selection can be stored in a genus or even a whole population of small size for a long time.This pattern often observed in a small population, which numbered no more than 1000 individuals, because in this case is extremely low migration.
In order to better understand the genetic drift, should be aware of these laws.When the allele frequency is 0 in the subsequent generations is not changed.If it reaches 1, then we say that a gene in the population is fixed.Random genetic drift is a consequence of the process of fixing with simultaneous loss of one allele.Most often, this regularity is observed when the mutation and migration does not cause permanent changes in the components of loci.
Since the frequency of genes is non-directional in nature, it reduces the diversity of species, but also increases the differences between local populations.It is worth noting that this counteracts the migration, in which different groups of organisms share their alleles.It should also be said that genetic drift has almost no effect on the frequency of individual genes in large populations, but in small groups, he can be a decisive factor in evolution.The number of alleles is changing dramatically.Some genes may be irretrievably lost, which greatly impoverishes the genetic diversity.
As an example, a massive epidemic, after which recovery of the population was carried out practically by a few of its representatives.Moreover, all the descendants of the ancestors had an identical gene.In the future expansion of the allelic diversity ensured importation manufacturers or exit bindings that promote the growth of differences at the genetic level.
extreme manifestation of genetic drift can be called the emergence of an entirely new population, which is formed from only a few individuals - the so-called founder effect.
should be noted that studies patterns of genome rearrangements biotechnology.Genetic engineering - is a technique of the science that allows you to transfer genetic information.This allows the transfer of genes to fight the species barrier and give organisms the necessary properties.
