Transposable genetic elements

Many examples of mobile elements are found in bacteria, where they are called transpo-sons. Bacterial transposons have terminal repeat sequences that both code for the enzymes catalyzing the process of transposition (transposases) and physically interact with these enzymes to bring them to the DNA target site. At this site the DNA-bound transposase presumably catalyzes the endonucleolytic cleavage of the terminal repeat sequence of the trahsposon and also catalyzes a similar sequence in the target DNA. 

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Transposable Genetic Elements Move from One Location to Another... 

Integrated viruses are also related to transposable genetic elements (transposons). These are segments of DNA that allow genes to move from place to place within the chromosomes (Chapter 27). 

Retroviruses Are RNA Viruses That Replicate through a DNA Intermediate Hepatitis B Virus Is a DNA Virus That Replicates through an RNA Intermediate Some Transposable Genetic Elements Encode a Reverse Transcriptase That Is Crucial to the Transposition Process... 

Some Transposable Genetic Elements Encode a Reverse Transcriptase That Is Crucial to the Transposition Process... 

The control of mating type in yeast illustrates a specialized role of mobile or transposable genetic elements in which mobile elements hop from one site to another. Mobile genetic elements are commonly found in both prokaryotes and eukaryotes, but most of them show little site specificity. Indeed, their almost random insertion behavior has led to the proposal that their major function in most cases is to promote evolutionary change. 

Until recently, the mechanisms for increasing the overall mutation rate were thought to involve DNA-copying enzymes or the process of DNA repair. However, high mutation rate is now known to be caused by another genetic mechanism—transposable genetic elements. 

Transposable genetic elements are DNA fragments containing genes that do not have a fixed location in a genome but can move from place to place within the genome, albeit with low frequency. 

See also Homologous Recombination, Site-Specific Recombination, Transposable Genetic Elements, Generating Antibody Diversity, Gene Rearrangements, Mechanisms of Protein Mutation (Chapter 7)... 

See also Transposable Genetic Elements, Site-Specific Recombination... 

Transposable Genetic Elements (Figure 25.34, Figure 25.35, Table 25.4, Figure 25.36, Figure 25.37)... 

Movable (or transposable) genetic elements, jumping genes, were first observed by Barbara McClintock in the 1940s. Her work, initially greeted with skepticism, was ultimately accepted, and she was awarded the Nobel Prize in 1983. 

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