Transposable element - Knowledge (XXG)

174:. These kernels came from a long line of plants that had been self-pollinated, causing broken arms on the end of their ninth chromosomes. As the maize plants began to grow, McClintock noted unusual color patterns on the leaves. For example, one leaf had two albino patches of almost identical size, located side by side on the leaf. McClintock hypothesized that during cell division certain cells lost genetic material, while others gained what they had lost. However, when comparing the chromosomes of the current generation of plants with the parent generation, she found certain parts of the chromosome had switched position. This refuted the popular genetic theory of the time that genes were fixed in their position on a chromosome. McClintock found that genes could not only move but they could also be turned on or off due to certain environmental conditions or during different stages of cell development. 1268:

sequence would have a T at this position as well, as the base pair is representative of the family as a whole at that particular position, and is most likely the base pair found in the family's ancestor at that position. Once a consensus sequence has been made for each family, it is then possible to move on to further analysis, such as TE classification and genome masking in order to quantify the overall TE content of the genome.

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allows mismatches, the number of which is determined by the analyst. Some k-mer approach programs use the k-mer as a base, and extend both ends of each repeated k-mer until there is no more similarity between them, indicating the ends of the repeats. Another group of algorithms employs a method called sequence self-comparison. Sequence self-comparison programs use databases such as

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frequency starts as a function once there is a distance from the TSS. A possible theory for this is that TEs might interfere with the transcription pausing or the first-intro splicing. Also as mentioned before, the presence of TEs closed by the TSS locations is correlated to their evolutionary age (number of different mutations that TEs can develop during the time).

474: 728:, two types of transposons combined to form noncoding RNA that catalyzes the development of stem cells. During the early stages of a fetus's growth, the embryo's inner cell mass expands as these stem cells enumerate. The increase of this type of cells is crucial, since stem cells later change form and give rise to all the cells in the body. 1303:

cis-regulatory region of the EO gene, which regulates molting hormone 20E, and enhanced expression was recorded. While populations without the TE insert are often unable to effectively regulate hormone 20E under starvation conditions, those with the insert had a more stable development, which resulted in higher developmental uniformity.

1032:, is a Tc1/mariner-like transposon. Its dead ("fossil") versions are spread widely in the salmonid genome and a functional version was engineered by comparing those versions. Human Tc1-like transposons are divided into Hsmar1 and Hsmar2 subfamilies. Although both types are inactive, one copy of Hsmar1 found in the 962:, chromatin remodeling and piRNA, such that little to no phenotypic effects nor movements of TEs occur as in some wild-type plant TEs. Certain mutated plants have been found to have defects in methylation-related enzymes (methyl transferase) which cause the transcription of TEs, thus affecting the phenotype. 1298:

to exhibit extended developmental time and reduced egg to adult viability. Although this adaptation was observed in high frequency in all non-African populations, it was not fixed in any of them. This is not hard to believe, since it is logical for a population to favor higher egg to adult viability,

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Recent studies have confirmed that TEs can contribute to the generation of transcription factors. However, how this process of contribution can have an impact on the participation of genome control networks. TEs are more common in many regions of the DNA and it makes up 45% of total human DNA. Also,

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on the sequence data, identifying periodicities, regions that are repeated periodically, and are able to use peaks in the resultant spectrum to find candidate repetitive elements. This method works best for tandem repeats, but can be used for dispersed repeats as well. However, it is a slow process,

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There is a hypothesis that states that TEs might provide a ready source of DNA that could be co-opted by the cell to help regulate gene expression. Research showed that many diverse modes of TEs co-evolution along with some transcription factors targeting TE-associated genomic elements and chromatin

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However, not all effects of adaptive TEs are beneficial to the population. In the research conducted in 2009, "A Recent Adaptive Transposable Element Insertion Near Highly Conserved Developmental Loci in Drosophila melanogaster", a TE, inserted between Jheh 2 and Jheh 3, revealed a downgrade in the

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Transposable elements have been recognized as good candidates for stimulating gene adaptation, through their ability to regulate the expression levels of nearby genes. Combined with their "mobility", transposable elements can be relocated adjacent to their targeted genes, and control the expression

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repeat identification, all operating under the same general principles. As short tandem repeats are generally 1–6 base pairs in length and are often consecutive, their identification is relatively simple. Dispersed repetitive elements, on the other hand, are more challenging to identify, due to the

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and due to the contribution to the formation of new cis-regulatory DNA elements that are connected to many transcription factors that are found in living cells; TEs can undergo many evolutionary mutations and alterations. These are often the causes of genetic disease, and gives the potential lethal

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New discoveries of transposable elements have shown the exact distribution of TEs with respect to their transcription start sites (TSSs) and enhancers. A recent study found that a promoter contains 25% of regions that harbor TEs. It is known that older TEs are not found in TSS locations because TEs

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is a sequence that is created based on the repeats that comprise a TE family. A base pair in a consensus is the one that occurred most often in the sequences being compared to make the consensus. For example, in a family of 50 repeats where 42 have a T base pair in the same position, the consensus

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Transposition can be classified as either "autonomous" or "non-autonomous" in both Class I and Class II TEs. Autonomous TEs can move by themselves, whereas non-autonomous TEs require the presence of another TE to move. This is often because dependent TEs lack transposase (for Class II) or reverse

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These three experiments all demonstrated different ways in which TE insertions can be advantageous or disadvantageous, through means of regulating the expression level of adjacent genes. The field of adaptive TE research is still under development and more findings can be expected in the future.

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from temperate climates, leading the researchers to conclude that the selective pressures of the climate prompted genetic adaptation. From this experiment, it has been confirmed that adaptive TEs are prevalent in nature, by enabling organisms to adapt gene expression as a result of new selective

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that had recently migrated from Africa to other parts of the world, as a basis for studying adaptations caused by transposable elements. Although most of the TEs were located on introns, the experiment showed a significant difference in gene expressions between the population in Africa and other

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approach, where a k-mer is a sequence of length k. In this approach, the genome is scanned for overrepresented k-mers; that is, k-mers that occur more often than is likely based on probability alone. The length k is determined by the type of transposon being searched for. The k-mer approach also

1251:. As these programs find groups of elements that partially overlap, they are useful for finding highly diverged transposons, or transposons with only a small region copied into other parts of the genome. Another group of algorithms follows the periodicity approach. These algorithms perform a 1508:

Altemose, Nicolas; Logsdon, Glennis A.; Bzikadze, Andrey V.; Sidhwani, Pragya; Langley, Sasha A.; Caldas, Gina V.; Hoyt, Savannah J.; Uralsky, Lev; Ryabov, Fedor D.; Shew, Colin J.; Sauria, Michael E. G.; Borchers, Matthew; Gershman, Ariel; Mikheenko, Alla; Shepelev, Valery A. (April 2022).

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At the same time, there have been several reports showing the advantageous adaptation caused by TEs. In the research done with silkworms, "An Adaptive Transposable Element insertion in the Regulatory Region of the EO Gene in the Domesticated Silkworm", a TE insertion was observed in the

970:(RNAi) mechanism. Surprisingly, the RNAi sequences are derived from the 5′ untranslated region (UTR) of the LINE1, a long terminal which repeats itself. Supposedly, the 5′ LINE1 UTR that codes for the sense promoter for LINE1 transcription also encodes the antisense promoter for the 1040:

The frequency and location of TE integrations influence genomic structure and evolution and affect gene and protein regulatory networks during development and in differentiated cell types. Large quantities of TEs within genomes may still present evolutionary advantages, however.

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TEs contributed to 16% of transcription factor binding sites. A larger number of motifs are also found in non-TE-derived DNA, and the number is larger than TE-derived DNA. All these factors correlate to the direct participation of TEs in many ways of gene control networks.

661:. This Class II transposable element is known for its uncanny ability to be transmitted horizontally in many species. There are an estimated 14,000 copies of Mariner in the human genome comprising 2.6 million base pairs. The first mariner-element transposons outside of 337:. Mechanism of transposition: Two transposases recognize and bind to TIR sequences, join and promote DNA double-strand cleavage. The DNA-transposase complex then inserts its DNA cargo at specific DNA motifs elsewhere in the genome, creating short TSDs upon integration. 752:

Transposons have coexisted with eukaryotes for thousands of years and through their coexistence have become integrated in many organisms' genomes. Colloquially known as 'jumping genes', transposons can move within and between genomes allowing for this integration.

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Some non-autonomous DNA TEs found in plants can capture coding DNA from genes and shuffle them across the genome. This process can duplicate genes in the genome (a phenomenon called transduplication), and can contribute to generate novel genes by exon shuffling.

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At the 1951 Cold Spring Harbor Symposium where she first publicized her findings, her talk was met with silence. Her work was largely dismissed and ignored until the late 1960s–1970s when, after TEs were found in bacteria, it was rediscovered. She was awarded a

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Transposable elements can be harnessed in laboratory and research settings to study genomes of organisms and even engineer genetic sequences. The use of transposable elements can be split into two categories: for genetic engineering and as a genetic tool.

1028:(inactive gene sequences). In vertebrate animal cells, nearly all 100,000+ DNA transposons per genome have genes that encode inactive transposase polypeptides. The first synthetic transposon designed for use in vertebrate (including human) cells, the 438:

Some researchers also identify a third class of transposable elements, which has been described as "a grab-bag consisting of transposons that don't clearly fit into the other two categories". Examples of such TEs are the Foldback (FB) elements of

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closes the sugar-phosphate backbone. This results in target site duplication and the insertion sites of DNA transposons may be identified by short direct repeats (a staggered cut in the target DNA filled by DNA polymerase) followed by

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This feature allows researchers to distinguish between genes that must be present inside of a cell in order to function (cell-autonomous) and genes that produce observable effects in cells other than those where the gene is

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gene is under selection as it provides DNA-binding for the histone-modifying protein. Many other human genes are similarly derived from transposons. Hsmar2 has been reconstructed multiple times from the fossil sequences.

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Despite the potential negative effects of retrotransposons, like inserting itself into the middle of a necessary DNA sequence, which can render important genes unusable, they are still essential to keep a species'

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While there are many positive effects of transposons in their host eukaryotic genomes, there are some instances of mutagenic effects that TEs have on genomes leading to disease and malignant genetic alterations.

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One hypothesis suggests that only approximately 100 LINE1 related sequences are active, despite their sequences making up 17% of the human genome. In human cells, silencing of LINE1 sequences is triggered by an

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TEs are also a widely used tool for mutagenesis of most experimentally tractable organisms. The Sleeping Beauty transposon system has been used extensively as an insertional tag for identifying cancer genes.

735:, a transposon in a gene called cortex caused the moths' wings to turn completely black. This change in coloration helped moths to blend in with ash and soot-covered areas during the Industrial Revolution. 6174: 3239:

Kazazian HH, Wong C, Youssoufian H, Scott AF, Phillips DG, Antonarakis SE (March 1988). "Haemophilia A resulting from de novo insertion of L1 sequences represents a novel mechanism for mutation in man".

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Miki Y, Nishisho I, Horii A, Miyoshi Y, Utsunomiya J, Kinzler KW, Vogelstein B, Nakamura Y (February 1992). "Disruption of the APC gene by a retrotransposal insertion of L1 sequence in a colon cancer".

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Sun W, Samimi H, Gamez M, Zare H, Frost B (August 2018). "Pathogenic tau-induced piRNA depletion promotes neuronal death through transposable element dysregulation in neurodegenerative tauopathies".

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enzymes. Some transposases non-specifically bind to any target site in DNA, whereas others bind to specific target sequences. The transposase makes a staggered cut at the target site producing

6167: 332:. Structure of DNA transposons (Mariner type). Two inverted tandem repeats (TIR) flank the transposase gene. Two short tandem site duplications (TSD) are present on both sides of the insert. 1179:

The Tc1/mariner-class of TEs Sleeping Beauty transposon system, awarded Molecule of the Year in 2009, is active in mammalian cells and is being investigated for use in human gene therapy.

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repeat identification is an initial scan of sequence data that seeks to find the repetitive regions of the genome, and to classify these repeats. Many computer programs exist to perform

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TEs are found in almost all life forms, and the scientific community is still exploring their evolution and their effect on genome evolution. It is unclear whether TEs originated in the

2832:"Recent horizontal transfer of mellifera subfamily mariner transposons into insect lineages representing four different orders shows that selection acts only during horizontal transfer" 1127:

In some cases the insertion of a TE into a gene can disrupt that gene's function in a reversible manner where transposase-mediated excision of the DNA transposon restores gene function.

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promoters and their rate of transposition increases if the cell is subjected to stress, thus increasing the mutation rate under these conditions, which might be beneficial to the cell.

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SanMiguel P, Tikhonov A, Jin YK, Motchoulskaia N, Zakharov D, Melake-Berhan A, et al. (November 1996). "Nested retrotransposons in the intergenic regions of the maize genome".

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bacterial strains can be generated in this way). Bacterial transposons of this type belong to the Tn family. When the transposable elements lack additional genes, they are known as

932:. Using several assumptions, the rate of successful transposition event per single Ty1 element came out to be about once every few months to once every few years. Some TEs contain 293:

Retroviruses can also be considered TEs. For example, after the conversion of retroviral RNA into DNA inside a host cell, the newly produced retroviral DNA is integrated into the

1049:, they protect novel gene sequences from being overwritten by similar gene sequences and thereby facilitate the development of new genes. TEs may also have been co-opted by the 1164:

expression of gene sequences. Also, this analytic technique mutates the desired locus of interest so that the phenotypes of the original and the mutated gene can be compared.

593:. They seem to have first appeared in the species only in the middle of the twentieth century; within the last 50 years, they spread through every population of the species. 307:

retrotransposon, which can produce RNA intermediates that may leave the host cell and infect other cells. The transposition cycle of retroviruses has similarities to that of

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Miura A, Yonebayashi S, Watanabe K, Toyama T, Shimada H, Kakutani T (May 2001). "Mobilization of transposons by a mutation abolishing full DNA methylation in Arabidopsis".

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caused by these elements. These changes in the genome could, for example, lead to a change in the color of corn kernels. About 64% of the maize genome consists of TEs. The

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fact that they are longer and have often acquired mutations. However, it is important to identify these repeats as they are often found to be transposable elements (TEs).

5344: 566: 186: 5197: 450: 3865:"The ancient mariner sails again: transposition of the human Hsmar1 element by a reconstructed transposase and activities of the SETMAR protein on transposon ends" 1068:

TEs can contain many types of genes, including those conferring antibiotic resistance and the ability to transpose to conjugative plasmids. Some TEs also contain

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Van't Hof, Arjen E.; Campagne, Pascal; Rigden, Daniel J. (1 June 2016). "The industrial melanism mutation in British peppered moths is a transposable element".

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McClintock also showed that gene mutations could be reversed. She presented her report on her findings in 1951, and published an article on her discoveries in

1001:. Various viruses and TEs also share features in their genome structures and biochemical abilities, leading to speculation that they share a common ancestor. 6797: 5337: 2979:"Transposable elements and genome organization: a comprehensive survey of retrotransposons revealed by the complete Saccharomyces cerevisiae genome sequence" 1124:

Insertional mutagenesis uses the features of a TE to insert a sequence. In most cases, this is used to remove a DNA sequence or cause a frameshift mutation.

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are another prominent class of transposons found in multiple species, including humans. The Mariner transposon was first discovered by Jacobson and Hartl in

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Bruno M, Mahgoub M, Macfarlan TS (December 2019). "The Arms Race Between KRAB-Zinc Finger Proteins and Endogenous Retroelements and Its Impact on Mammals".

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If organisms are mostly composed of TEs, one might assume that disease caused by misplaced TEs is very common, but in most cases TEs are silenced through

121:, many are important in genome function and evolution. Transposons are also very useful to researchers as a means to alter DNA inside a living organism. 4237:

Saha S, Bridges S, Magbanua ZV, Peterson DG (2008). "Computational Approaches and Tools Used in Identification of Dispersed Repetitive DNA Sequences".

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of each family of sequences, and 3) classify these repeats. There are three groups of algorithms for the first step. One group is referred to as the

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that becomes the substrate for siRNA production. Inhibition of the RNAi silencing mechanism in this region showed an increase in LINE1 transcription.

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Yang N, Kazazian HH (September 2006). "L1 retrotransposition is suppressed by endogenously encoded small interfering RNAs in human cultured cells".

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TEs are used for the reconstruction of phylogenies by the means of presence/absence analyses. Transposons can act as biological mutagen in bacteria.

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are evolving from TE sequences. Most of the time, these particular modes do not follow the simple model of TEs and regulating host gene expression.

381:, when a donor site has already been replicated but a target site has not yet been replicated. Such duplications at the target site can result in 2218:

Kaminker JS, Bergman CM, Kronmiller B, Carlson J, Svirskas R, Patel S, Frise E, Wheeler DA, Lewis SE, Rubin GM, Ashburner M, Celniker SE (2002).

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The cut-and-paste transposition mechanism of class II TEs does not involve an RNA intermediate. The transpositions are catalyzed by several

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Belancio VP, Hedges DJ, Deininger P (March 2008). "Mammalian non-LTR retrotransposons: for better or worse, in sickness and in health".

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Mustajoki S, Ahola H, Mustajoki P, Kauppinen R (June 1999). "Insertion of Alu element responsible for acute intermittent porphyria".

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Jiang N, Bao Z, Zhang X, Eddy SR, Wessler SR (September 2004). "Pack-MULE transposable elements mediate gene evolution in plants".

2161:"Multigenome analysis implicates miniature inverted-repeat transposable elements (MITEs) in metabolic diversification in eudicots" 6802: 6732: 1336: 1083:

Transposons do not always excise their elements precisely, sometimes removing the adjacent base pairs; this phenomenon is called

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carries a large and diverse number of TEs. This analysis by Matthews et al. 2018 also suggests this is common to all mosquitoes.

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Bucher E, Reinders J, Mirouze M (November 2012). "Epigenetic control of transposon transcription and mobility in Arabidopsis".

4587:"An adaptive transposable element insertion in the regulatory region of the EO gene in the domesticated silkworm, Bombyx mori" 6655: 6005: 5600: 5183: 983: 1280:

The study conducted in 2008, "High Rate of Recent Transposable Element–Induced Adaptation in Drosophila melanogaster", used

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within genomes are created by transposition events accumulating over evolutionary time. Because interspersed repeats block

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system operates by a mechanism similar to that of some TEs. TEs also serve to generate repeating sequences that can form

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Insertion of L1 into the APC gene causes colon cancer, confirming that TEs play an important role in disease development.

201:. TEs are assigned to one of two classes according to their mechanism of transposition, which can be described as either 5789: 4669: 1154: 3779:

Plasterk RH, Izsvák Z, Ivics Z (August 1999). "Resident aliens: the Tc1/mariner superfamily of transposable elements".

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Mills RE, Bennett EA, Iskow RC, Devine SE (April 2007). "Which transposable elements are active in the human genome?".

5709: 5465: 4487:"A recent adaptive transposable element insertion near highly conserved developmental loci in Drosophila melanogaster" 897: 628:

DNA and back, allowing for the transfer and permanent addition of genes such as those encoding antibiotic resistance (

492: 3816:"Molecular reconstruction of Sleeping Beauty, a Tc1-like transposon from fish, and its transposition in human cells" 6807: 5040: 4682: 2611:

Spradling AC, Rubin GM (October 1982). "Transposition of cloned P elements into Drosophila germ line chromosomes".

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system described by McClintock are Class II TEs. Transposition of Ac in tobacco has been demonstrated by B. Baker.

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Rubin GM, Spradling AC (October 1982). "Genetic transformation of Drosophila with transposable element vectors".

1381: 678: 562: 496: 393: 3180:"Genome-wide analysis in the mouse embryo reveals the importance of DNA methylation for transcription integrity" 881:

into the PBGD gene leads to interference with the coding region and leads to acute intermittent porphyria (AIP).

6660: 5857: 5758: 5675: 5280: 5210: 5175: 987: 928: 819: 686: 224: 1855:"Proceedings of the National Academy of Sciences Dec 2012, 109 (50) 20198-20199; DOI: 10.1073/pnas.1219372109" 166:

In the winter of 1944–1945, McClintock planted corn kernels that were self-pollinated, meaning that the silk (

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LINE1(L1) TE's and other retrotransposons have been linked to cancer because they cause genomic instability.

583: 198: 118: 2791:"Horizontal transmission, vertical inactivation, and stochastic loss of mariner-like transposable elements" 461:

Approximately 64% of the maize genome is made up of TEs, as is 44% of the human genome, and almost half of

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is then inserted back into the genome at a new position. The reverse transcription step is catalyzed by a

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TEs use a number of different mechanisms to cause genetic instability and disease in their host genomes.

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Ricci, Marco; Peona, Valentina; Guichard, Etienne; Taccioli, Cristian; Boattini, Alessio (31 May 2018).

1341: 1244: 1008:, many organisms have acquired mechanisms to inhibit their activity. Bacteria may undergo high rates of 903:

Caused by SVA transposable element insertion in the fukutin (FKTN) gene which renders the gene inactive.

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Makałowski W, Pande A, Gotea V, Makałowska I (2012). "Transposable elements and their identification".

3995:"A retrotransposon gag-like-3 gene RTL3 and SOX-9 co-regulate the expression of COL2A1 in chondrocytes" 5142: 5060: 3993:

Ball, Hope C.; Ansari, Mohammad Y.; Ahmad, Nashrah; Novak, Kimberly; Haqqi, Tariq M. (November 2021).

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identification of transposons involves three steps: 1) find all repeats within the genome, 2) build a

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Use of the Sleeping Beauty Transposon System for Stable Gene Expression in Mouse Embryonic Stem Cells

4664: 4143: 4100: 3947: 3735: 3579: 3427: 3191: 3102: 3033: 2933: 2743: 2663: 2620: 2553: 2482: 2336: 2278: 2172: 1805: 1579: 1196: 1080:. There are over 40 antibiotic resistance genes identified on cassettes, as well as virulence genes. 940: 629: 267: 31: 3664:

Kidwell MG (1992). "Horizontal transfer of P elements and other short inverted repeat transposons".

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Transposable element dysregulation can cause neuronal death, leading to neurodegenerative disorders

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A transposon or a retrotransposon that inserts itself into a functional gene can disable that gene.

707: 647:. It is approximately 300 bases long and can be found between 300,000 and one million times in the 277:(LINEs, LINE-1s, or L1s), which encode reverse transcriptase but lack LTRs, and are transcribed by 140:, which they require for insertion and excision, and some of these TEs also encode other proteins. 243:, which is often encoded by the TE itself. The characteristics of retrotransposons are similar to 6628: 6550: 6102: 5087: 4995: 4970: 4814: 4254: 4167: 3845: 3689: 3646: 3603: 3451: 3317: 3065: 2902: 2591: 2444: 2302: 2098: 1989: 1457:

Bourque G, Burns KH, Gehring M, Gorbunova V, Seluanov A, Hammell M, et al. (November 2018).

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Transposable elements make up a large fraction of the genome and are responsible for much of the

91: 4651:- a database of transposable element families, multiple sequence alignments, and sequence models 4187:"Mobilization of Pack-CACTA transposons in Arabidopsis suggests the mechanism of gene shuffling" 4091:

Moran JV, DeBerardinis RJ, Kazazian HH (March 1999). "Exon shuffling by L1 retrotransposition".

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Paquin CE, Williamson VM (October 1984). "Temperature effects on the rate of ty transposition".

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Kazazian HH, Goodier JL (August 2002). "LINE drive. retrotransposition and genome instability".

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Dahlet T, Argüeso Lleida A, Al Adhami H, Dumas M, Bender A, Ngondo RP, et al. (June 2020).

82:. Transposition often results in duplication of the same genetic material. In the human genome, 6606: 6522: 6424: 6194: 6097: 5801: 5065: 4608: 4567: 4516: 4464: 4410: 4358: 4306: 4296: 4216: 4159: 4116: 4073: 4032: 4014: 3975: 3894: 3837: 3796: 3761: 3681: 3638: 3595: 3549: 3500: 3443: 3405: 3372: 3347: 3309: 3279: 3257: 3217: 3165: 3132: 3114: 3057: 3049: 3000: 2959: 2894: 2853: 2812: 2771: 2679: 2636: 2579: 2510: 2436: 2397: 2362: 2294: 2251: 2220:"The transposable elements of the Drosophila melanogaster euchromatin: a genomics perspective" 2200: 2121: 2090: 2050: 1981: 1938: 1911: 1905: 1886: 1835: 1755: 1693: 1658: 1607: 1548: 1530: 1490: 1429: 1406: 1387: 554: 278: 5030: 4980: 4975: 1020:

to inhibit TE activity. Nevertheless, some TEs generate large families often associated with

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Kazazian HH, Moran JV (May 1998). "The impact of L1 retrotransposons on the human genome".

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Gil E, Bosch A, Lampe D, Lizcano JM, Perales JC, Danos O, Chillon M (11 September 2013).

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Carlton JM, Hirt RP, Silva JC, Delcher AL, Schatz M, Zhao Q, et al. (January 2007).

986:, arose independently multiple times, or arose once and then spread to other kingdoms by 923: 616:, TEs usually carry an additional gene for functions other than transposition, often for 163:

in New York. McClintock was experimenting with maize plants that had broken chromosomes.

4433:"High rate of recent transposable element-induced adaptation in Drosophila melanogaster" 4147: 4104: 3951: 3739: 3583: 3431: 3195: 3037: 2937: 2747: 2667: 2624: 2557: 2486: 2432: 2340: 2282: 2176: 1583: 1285:

parts of the world. The four TEs that caused the selective sweep were more prevalent in

1072:, genetic elements that can capture and express genes from other sources. These contain 811:

Expression of disease-causing, damaging proteins that inhibit normal cellular function.

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Not all DNA transposons transpose through the cut-and-paste mechanism. In some cases, a

17: 6515: 6480: 6473: 6452: 6431: 6408: 6288: 6080: 5967: 5838: 5697: 5680: 5485: 5415: 5132: 4990: 4947: 4775: 4765: 4562: 4535: 4511: 4486: 4459: 4432: 4405: 4380: 4353: 4328: 4211: 4186: 4027: 3994: 3970: 3935: 3889: 3864: 3756: 3724:"Transposable Elements Activity is Positively Related to Rate of Speciation in Mammals" 3723: 3544: 3520:"Endogenous RNA interference provides a somatic defense against Drosophila transposons" 3519: 3401: 3212: 3179: 3127: 3084: 2954: 2921: 2574: 2541: 2505: 2470: 2357: 2324: 2195: 2160: 1960:"A universal classification of eukaryotic transposable elements implemented in Repbase" 1881: 1854: 1830: 1653: 1626: 1602: 1567: 1543: 1510: 1485: 1458: 1351: 1084: 948: 350: 320: 167: 133: 103: 5329: 4630: 3832: 3815: 3792: 3495: 3470: 2766: 2731: 2246: 2236: 2219: 1149:

In addition to the qualities mentioned for Genetic engineering, a Genetic tool also:-

780:

After a DNA transposon leaves a gene, the resulting gap may not be repaired correctly.

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in 1983 for her discovery of TEs, more than thirty years after her initial research.

4381:"Transposable elements donate lineage-specific regulatory sequences to host genomes" 4258: 3849: 3693: 3650: 3455: 2306: 2102: 826:. These promoters can cause aberrant expression of linked genes, causing disease or 39: 6771: 6704: 6568: 6536: 6501: 6487: 6459: 6385: 6364: 6107: 5950: 5910: 5877: 5649: 5635: 5533: 5313: 5260: 5109: 4171: 3607: 3321: 3069: 1993: 1263:

repeat identification involves building a consensus of each family of sequences. A

922:

One study estimated the rate of transposition of a particular retrotransposon, the

784: 648: 644: 4112: 4010: 2922:"Draft genome sequence of the sexually transmitted pathogen Trichomonas vaginalis" 2732:"Molecular structure of a somatically unstable transposable element in Drosophila" 4449: 4292: 3960: 2906: 2290: 2142: 1749: 939:

Cells defend against the proliferation of TEs in a number of ways. These include

578:, TEs play such a critical role that when removed, the organism fails to develop. 403:

Class II TEs comprise less than 2% of the human genome, making the rest Class I.

6633: 6378: 6131: 5997: 5945: 5940: 5453: 5318: 5275: 5104: 5015: 4877: 3863:

Miskey C, Papp B, Mátés L, Sinzelle L, Keller H, Izsvák Z, Ivics Z (June 2007).

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Nowacki M, Higgins BP, Maquilan GM, Swart EC, Doak TG, Landweber LF (May 2009).

2031: 1821: 1361: 991: 955: 878: 857:(L1) TEs that land on the human Factor VIII have been shown to cause haemophilia 823: 550: 367: 346: 342: 308: 181:

in November 1953 entitled "Induction of Instability at Selected Loci in Maize".

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