Gene recombination is the exchange of genetic material between different organisms. It leads to the production of offspring with combinations of traits that are different from those found in both parents. Most of these genetic exchanges occur naturally.
How is going
Recombination of genes begins as a result of the separation of genes during gamete formation in meiosis, fertilization and crossbreeding. Intersection allows alleles on DNA molecules to change position from one homologous segment of a chromosome to another. Recombination is responsible for the genetic diversity of a species or population.
Chromosome structure
Chromosomes are located inside the nucleus of cells. They are formed from chromatin - a mass of genetic material consisting of DNA that is tightly entwined around proteins called histones. The chromosome is usually single-stranded and consists of a centromere region that connects the long and short regions.
Chromosome duplication
When a cell enters its life cycle, its chromosomes are duplicated through DNA replication in preparation for division. Each duplicated chromosome consists of two identical, called sister chromatids. They are associated with the centromere region. In cell division, paired sets are formed. They consist of one chromosome (homologous) from each parent.
Chromosome exchange
Cross -over gene recombination was first described by Thomas Hunt Morgan. In eukaryotes, it is facilitated by chromosomal intersection. The process of crossing leads to the fact that the offspring has various combinations of genes and can produce new chimeric alleles. This allows sexually transmitted organisms to avoid Möller ratchet, in which the genomes of the asexual population accumulate genetic deletions irreversibly.
During prophase I, four chromatids are tightly connected. In this formation, homologous sites on two molecules can closely pair with each other and exchange genetic information. Recombination of genes can occur anywhere along the chromosome. Its frequency between two points depends on the distance separating them.
Value
Tracking the movement of genes as a result of crossovers has been very useful for geneticists. This makes it possible to determine how far apart are the two genes on the chromosome. Science can also use this method to infer the presence of certain genes. One molecule in a coupled pair serves as a marker to detect the presence of another. It is used to detect the presence of pathogenic genes.
The recombination frequency between two observed loci is the intersection value. It depends on the mutual distance of the observed genetic foci. For any fixed set of environmental conditions, recombination in a certain region of the bond structure (chromosomes) tends to be constant. The same is true for the intersection value that is used when creating genetic maps.
Meiosis
Chromosomal crossover involves the exchange of paired chromosomes inherited from each of the parents. Meiosis, as the basis for gene recombination, plays an important role in this process. Molecular models of this process have evolved over the years as relevant evidence has accumulated. The new model demonstrates: two of the four chromatids present at the beginning of meiosis (prophase I) are paired with each other and able to interact. In it there is a recombination of chromosomes and genes. However, explanations for the adaptive function of meiosis, which focus solely on intersection, are insufficient for most metabolic events.
Mitosis and non-homologous chromosomes
In eukaryotic cells, crossbreeding can also occur during mitosis. In this case, two cells with identical genetic material are obtained. Any crossover that occurs between homologous chromosomes in mitosis does not produce a new gene combination.
An intersection that occurs on non-homologous chromosomes can produce a mutation known as translocation. It occurs when a segment of a chromosome separates from and moves to a new position on a non-homologous molecule. This type of mutation can be dangerous, as it often leads to the development of cancer cells.
Gene conversion
When converting genes, part of the genetic material is copied from one chromosome to another without changing the donor. Gene conversion occurs at a high frequency in the actual location. This is the process by which a DNA sequence is copied from one helix to another. The recombination of genes and chromosomes was studied in fungal crosses, where it is convenient to observe four products of individual meioses. Gene conversion events can be distinguished as deviations in individual cell division from normal segregation 2: 2.
Genetic Engineering
Recombination of genes can be artificial and intentional. It is used on disparate DNA fragments, often from different organisms. Thus, recombinant DNA is obtained . Artificial recombination can be used to add, remove or modify body genes. This method is important for biomedical research in the field of genetic and protein engineering.
Recombinant Recovery
During mitosis and meiosis, DNA damaged by various exogenous factors can be saved by the homologous recovery step (FGP). In humans and rodents, deficiencies in the gene products needed for FGP during meiosis cause infertility.
In bacteria, transformation is the process of gene transfer that usually occurs between individual cells of the same species. It involves the integration of donor DNA into the recipient chromosome by recombination of genes. This process is an adaptation to repair damaged cells. Transformation can benefit pathogenic bacteria by allowing the repair of DNA damage that occurs in an inflammatory, oxidative environment associated with a host infection.
When two or more viruses, each of which contains fatal genomic damage, infect the same host cell, the genomes can mate with each other and pass the FGP to produce viable offspring. This process is called reactivation of multiplicity. It has been studied in several pathogenic viruses.
Recombination in Prokaryotic Cells
Prokaryotic cells, like unicellular bacteria without a nucleus, also undergo genetic recombination. In this case, the genes of one bacterium are included in the genome of another by crossing. Bacterial recombination is carried out by conjugation, transformation or transduction processes.
In conjugation, one bacterium binds to another through a protein tubular structure. In the process of transformation, prokaryotes take DNA from the environment. They most often come from dead cells.
During transduction, DNA is exchanged through a virus that infects bacteria known as a bacteriophage. Once a foreign cell is internalized through conjugation, transformation, or transduction, the bacterium can insert its segments into its own DNA. This transmission is carried out by crossing and leads to the creation of a recombinant bacterial cell.