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Genes are an important part of the existence of life. They contain all the information that dictates what processes should be carried out, what molecules should be formed and what the phenotypic traits of each organism will be like. This information is transmitted from parents to their offspring, but how does this happen? In this Green Ecologist article you will learn what is genetic recombination and types in order to understand this important process that allows genetic information to be transferred from one generation to another.
What is genetic recombination and where does it occur?
Genetic recombination is the process in which new DNA is formed from a combination of two genetic sequences. The new DNA will be unique and will contain combined information from the parent sequences.
There are different types of genetic recombination that we will review later, and therefore recombination can occur at different locations in different organisms. These places are:
- Eukaryotic cells: during prophase of meiosis I for the production of gametes. Here, the strands of chromosomes are paired to create the new DNA. Here you can find more information about the Difference between eukaryotic and prokaryotic cell.
- In bacteria and viruses: in this case we find three types of mechanisms. The transformation receives exogenous DNA fragments to exchange genetic information with the recipient. The conjugation occurs between two bacteria through the sexual pili, a type of connection that occurs between two cells, one is a donor of genetic material and the other is a recipient. By last, transduction It occurs when a virus transfers genetic information between bacteria, without the need for the bacteria to communicate with each other to exchange information. This is how recombination also takes place during the infection of bacterial plasmids or viruses. If you want to know the Difference between viruses and bacteria, do not hesitate to take a look at this other Green Ecologist article that we recommend.
The recombination process comprises different types. We will go through one by one so that you can better understand this important process.
Types of genetic recombination
As we mentioned in the previous section, there are different types of genetic recombination. Therefore, below we are going to detail them one by one.
Homologous recombination
This type of recombination occurs when sperm and ovules are formed, in meiosis, and with extensively homologous genetic sequences. During this process, the female and male chromosomes line up so that similar DNA sequences intersect. Results in the genetic variability created by the great variety of crossovers. If you want to understand more about the subject, here you can read about the Difference between mitosis and meiosis.
In this category is classified V (D) J recombination, which works for the immune system of vertebrates. Here they encode proteins to create a large number of lymphocytic cells and immunoglobulins.
Site-specific or non-homologous recombination
In this case, the sequences do not need to be very similar as in the case of homologous recombination, but rather it occurs in small fragments of nearly identical sequences, where specific proteins such as integrase can help complete recombination. Here, it is not homology that dominates recombination, but rather the relationship between DNA and proteins.
Transposition
In this mechanism, segments of DNA or RNA called transposons can jump to other sites in the genome. Here there is no homologation mechanism, but rather are inserted without being similar, causing mutations. Its frequency is very low, and an example of the mechanism is resistance to antibiotics. The most resistant strains survive the medication, and their genes can be spread by rearrangement.
Why is genetic recombination important?
Genetic recombination is one of the most important processes for the continuity of genetic material. Therefore, we are going to present some of the reasons for the importance of genetic recombination.
- Allows you to create new combinations: from two initial sequences. In this process of natural selection, hundreds of different combinations can even be created from two initial DNAs, as occurs in human siblings of equal parents.
- Essential for genetic diversity: extremely important attribute that allows unsuitable organisms to be replaced by others that are. In the absence of diversity, the options would be narrowed and the survival of the species would be jeopardized. The lack of variation of species affects the prolongation of diseases, the lack of adaptation to the environment and of resilience to sudden environmental changes.
- Avoid the divergence of repeated sequences: that is, of recessive genes that can have harmful or lethal consequences to organisms. During genetic divergence, there is no longer any genetic swapping or recombination and this is reduced by recombination.
- Prevents the formation of the Müllerian Ratchet: it is a phenomenon that occurs in asexual organisms with progeny identical to the initial one. Being equal organisms, mutated and harmful genes accumulate.
- Represents a genetic regulator: can turn genes on or off. This occurs frequently in transposition, where the continuity of the gene where the transposon was inserted is interrupted. An example of this is the varied coloration of the corn kernels. This mechanism is also important for the maintenance and repair of the genome. It occurs mainly in homologous recombinationBecause during the process, breaks are usually made in the female DNA, called double-stranded breaks, and the sequence homologation mechanism repairs these sections.
- Helps chromosomes separate: takes place during meiosis. Here the crossing occurs where homologous chromosomes can separate and unite in a complementary way.
- Allows the immune system to function in vertebrates: since it is thanks to V (D) J recombination, where a huge range of antibodies is created in the face of the multiple threats that are in the environment.
After all, genetic recombination is the result of the reproductive function. Therefore, we leave you this other article about the Playback function: what it is and why it is important, so that you can have more knowledge on the subject.
If you want to read more articles similar to Genetic recombination: what is it and types, we recommend that you enter our Biology category.
Bibliography- Ostrander, E. (2022). Homologous recombination. Available at: https://www.genome.gov/es/genetics-glossary/Recombinacion-homologa
- Claros, G. (s.f.) DNA rearrangement: recombination. Available at: http://www.biorom.uma.es/con entente/av_bma/apuntes/T8/t8_recomb.htm
- University of Havana. (2022). DNA recombination. Available at: http://www.fbio.uh.cu/sites/genmol/confs/conf5/
- Barrios, J. (2014). Genetic recombination in prokaryotes. Available at: https://www.ucm.es/data/cont/media/www/pag-56185/19-La%20recombinaci%C3%B3n%20gen%C3%A9tica%20en%20procariontes.pdf
