What are the functions of jumping genes? Transposons (jumping genes) are DNA sequences in the genome of a cell that move to another part of the genome. This movement of transposons within the genome is called transposition. As a result of the displacement, mutations occur with the observation of changes in the amount of DNA in the genome.
Types and discovery of transposons
Transposons are divided into two categories according to their mechanisms of action: retrotransposons and DNA transposons. Retrotransposons replicate themselves with an RNA intermediate and transpose within the genome, whereas DNA transposons transpose using “copying” and “cutting” mechanisms without the use of RNA material.
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Transposons were discovered in 1948 as a result of Barbara McClintock’s studies on maize plants. The studies were carried out in the 1940s on insertions and deletions that occurred in a large part of the DNA, referred to as junk DNA. The insertions and deletions were found to be caused by the substitution of Ac/Ds-type retrotransposons, which cause color changes in maize grains and account for 85% of the maize genome. McClintock was awarded the Nobel Prize in 1983 for his work.
What is the role of jumping genes in the evolutionary process?
Scientists have been studying why transposons are needed in the evolutionary process, and although the root causes have not been fully identified, it is thought that transposons are descended from a common ancestor due to their similarities with retroviruses during replication.
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In the evolutionary process, when organisms are exposed to too many transposons, their genomes become completely dysfunctional and organisms use defense mechanisms against transposons. For example, RNA in bacteria destroys jumping transposons. Although transposons have played a role in the development of many diseases in the evolutionary process, there have also been cases where the inserted gene has benefited the organism. In these cases, the gene was preserved and passed on to other generations.
References:
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Mammalian Retroelements
3. McCLINTOCK, B. (Haziran 1950). "The origin and behavior of mutable loci in
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4. R. H. A. Plasterk, et al. Resident Aliens: The Tc1/Mariner Superfamily Of
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Alındığı Tarih: 23 Mart 2019. Alındığı Yer: Cell
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