Nuclear DNA , nuclear deoxyribonucleic acid nDNA , is DNA contained within a cell nucleus nucleus of eukaryote eukaryotic organisms . ref http medical dictionary.thefreedictionary.com DNADNA definition in the Medical dictionary ref In mammals and vertebrate s, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than matrilineally . ref http en.mimi.hu biology nuclear genome.html Nuclear genome ref Nuclear DNA is the most common DNA used in forensic examinations. ref http www.fbi.gov about us lab dna nuclear FBI Laboratory Services Nuclear DNA Unit ref References reflist See also Nuclear gene Chromatin Nucleic acids DEFAULTSORT Nuclear Dna Category DNA Cell biology stub ar ca ADN nuclear fr ADN nucl aire pl NDNA pt DNA nuclear ... more details
Naked DNA is histone free DNA that is passed from cell to cell during a gene transfer process called transformation genetics transformation or transfection . In transformation, purified or naked DNA is taken up by the recipient cell which will give the recipient cell a new characteristic or phenotype . Transfection differs from transformation since the DNA is not generally incorporated into the cell s genome, it is only transiently expressed. In the field of DNA vaccines or genetic immunization, the term naked DNA was coined by Vical to mean DNA delivered free from agents which promote transfection. Research on the use of naked DNA for DNA vaccination s and gene therapy has shown some initial success, but have not yet resulted in any generally available therapy. External links http www.niaid.nih.gov daids vaccine dna.htm Naked DNA vaccine research http 202.54.26.221 DyNAVacS an Integrative Tool for DNA Vaccine Design hosted at the Institute of Genomics and Integrative Biology. Category DNA genetics stub ur ... more details
Refimprove date January 2009 Circular DNA is a form of DNA that is found in viruses , bacteria and archaea as well as in eukaryote eukaryotic cells in the form of either mitochondrial DNA or plastid DNA. While the individual strands of a linear double helix represent two distinct and separable molecules, this need not be true for circular DNA . If the strands twist an odd number of times around one another in completing the DNA loop, then they are covalent bond covalently joined into a single molecule. Citation needed date November 2010 See also Plasmid Supercoil Yeast artificial chromosome Bacterial artificial chromosome M bius strip Fruit genetics stub Microbiology stub Category DNA DEFAULTSORT Circular Dna fr ADN circulaire pt DNA circular ... more details
Image Mitochondrial DNA en.svg thumb 300px right Human mitochondrial DNA. File Electron microscopy reveals mitochondrial DNA in discrete foci.jpg thumb Electron microscopy reveals mitochondrial DNA in discrete foci. Bars 200 nm. A Cytoplasmic section after immunogold labelling with anti DNA gold particles ... extraction with CSK buffer and immunogold labelling with anti DNA mtDNA marked by gold particles resists ... www.biomedcentral.com 1741 7007 2 9 ref Mitochondrial DNA mtDNA or mDNA ref cite web last Sykes first B title Mitochondrial DNA and human history url http genome.wellcome.ac.uk doc WTD020876.html work ... September 2003 ref is the DNA located in organelles called mitochondrion mitochondria , structures ... triphosphate ATP . Most other DNA present in eukaryotic organisms is found in the cell nucleus . Mitochondrial DNA can be regarded as the smallest chromosome , and was the first significant part ... from the mother. The DNA sequence of mtDNA has been determined from a large number of organisms and individuals including some organisms that are extinct , and the comparison of those DNA sequences ... has become important in anthropology and field biology. Origin Nuclear and mitochondrial DNA are thought to be of separate evolution ary origin, with the mtDNA being derived from the circular DNA circular ... target molecules by exponential polymerase chain reaction, copy number of mitochondrial DNA in rat ... DNA , but the genes for some of them, if not most, are thought to have originally been of bacterial ... injecting a sperm into an oocyte , may interfere with this. The fact that mitochondrial DNA .... Y chromosome Y chromosomal DNA , paternally inherited, is used in an analogous way to trace the agnate ... region s HVR1 or HVR2 of the mitochondrial DNA, as with a genealogical DNA test . HVR1 consists ... either specific people or subjects in a database to determine maternal lineage. Most often, the comparison ... limited biparental inheritance of Mytilus mitochondrial DNA journal Science volume 251 pages 1488 1490 ... more details
Unreferenced date March 2009 About the biotechnological tool the laboratory phenomenon DNA laddering Image DNAgel4wiki.png thumb An agarose gel with a 1 kb ladder, far right A DNA ladder is a solution of DNA molecules of different lengths used in agarose gel electrophoresis . It is applied to an agarose gel as a reference to estimate the size of unknown DNA molecules. In addition it can be used to approximate the mass of a band by comparison to a special mass ladder. Structure Different DNA ladders are commercially available depending on expected DNA length. The 1kb ladder with fragment ranging from about 0.5 kbp to 10 or 12 kbp and the 100 bp ladder with fragments ranging from 100 Base pair bp to just above 1000 bp are the most frequent. DNA ladders are often produced by a suitable restriction digest of a plasmid . There are special DNA ladders for DNA Supercoiled DNA supercoiled DNA and RNA. For example, a DNA HindIII Digest a common lambda DNA ladder that has band sizes in base pair s of 23,130 9,416 6,557 4,361 2,322 2,027 564 and 125 bp Category Biotechnology Category Biological techniques and tools ar de DNA Leiter fr Marqueur de poids mol culaire nl DNA ladder ... more details
Orphan date February 2009 C DNA also known as C form DNA . It is one of the many possible double helical structures of DNA . This form of DNA can be observed at some conditions such as relatively low humidity and the presence of certain ions , such as Li sup sup or Mg sup 2 sup . Recent research suggests that both C DNA and B DNA consist of two distinct nucleotide Conformational isomerism conformation s, B I and B II. The ratio of B II conformation in C DNA is more than 40 . However, the ratio of B II conformation in B DNA is only about 10 . See also B DNA A DNA Mechanical properties of DNA References cite journal author L van Dam, M H Levitt title BII nucleotides in the B and C forms of natural sequence polymeric DNA A new model for the C form of DNA journal J Mol Biol volume 304 issue 4 pages 541 61 year 2000 pmid 11099379 doi 10.1006 jmbi.2000.4194 Biochem stub Nucleic acids Category DNA zh C DNA ... more details
orphan date September 2010 It is a DNA contained in organelle s, outside the cell nucleus nucleus of eukaryote Eukaryotic cells . Examples mitochondria contain mitochondrial DNA plastid s e.g., chloroplasts contain plastid DNA Structure Unlike nuclear DNA , which is present as linear molecule s inside the chromosome s, organellar DNA is present as circular molecules of high copy number. Also, because organelles are uniparentally inherited in many organisms, so is their organellar DNA. See also Nuclear DNA Category DNA biology stub ar ... more details
Touch DNA is a forensic method for analyzing DNA left at the scene of a crime. It is called touch DNA because it only requires very small samples, for example from the skin cells left on an object after it has been touched or casually handled. ref http www.nfstc.org pdi Subject09 pdi s09 m01 03.htm Low Copy Number DNA nfstc.org ref Touch DNA analysis only requires seven or eight cells from the outermost layer of human skin. ref cite news title What is touch DNA? publisher Scientific American date 2008 08 08 url http www.scientificamerican.com article.cfm?id experts touch dna jonbenet ramsey ref The technique has been criticized for high rates of false positives due to contamination for example fingerprint brushes used by crime lab crime scene investigators can transfer trace amounts of skin cells from one surface to another, leading to inaccurate results. ref http www.theforensicinstitute.com news low copy number dna and the forensic institute.html Low Copy Number DNA and The Forensic Institute ref The technique is very similar to Low copy number Low Copy Number DNA analysis, to the extent that court rulings have sometimes confused the two. ref name law http www.personal.psu.edu dhk3 blogs DoubleHelixLaw 2010 07 scientists inability to agree on what to call dna profiling with really small samples confuses court.html Disagreement on What to Call DNA Profiling with Really Small Samples Confuses Courts Penn State University ref In LCN DNA analysis, the DNA goes through additional cycles of PCR amplification. ref name law Touch DNA helped determine the innocence and secure the release of Tim Masters from a prison in Colorado in 2008. Masters had been convicted of the murder of Peggy Hettrick and sentenced to life in prison in 1999. ref http dnaforensics.com TouchDNA.aspx Touch DNA from DNA Forensics ref See Also Low copy number LCN DNA , a similar method to obtain DNA profiles from very small samples. References reflist biology stub Category DNA profiling techniques ... more details
for the various methods Nucleic acid methods DNA isolation is a routine procedure to collect DNA for subsequent ... optional steps in a DNA extraction Breaking the Cell biology cells open, commonly referred to as cell disruption or cell lysis , to expose the DNA within. This is commonly achieved by chemical and physical ... done . Removing RNA by adding an RNase often done . Precipitating the DNA with an alcohol &mdash usually ice cold ethanol or isopropanol . Since DNA is insoluble in these alcohols, it will aggregate ... Mg sup 2 sup and calcium Ca sup 2 sup , which prevents enzymes like DNase from degrading the DNA. Cellular and histone proteins bound to the DNA can be removed either by adding a protease or by having ... extraction extracted them with a phenol chloroform mixture prior to the DNA precipitation. If desired, the DNA can be resolubilized in a slightly alkaline buffer or in ultra pure water. Special Types of DNA Extractions A Hirt DNA Extraction is an isolation of all extrachromosomal DNA in a mammalian cell. The Hirt extraction process gets rid of the high molecular weight nuclear DNA , leaving only low molecular weight mitochondrial DNA and any viral episomes present in the cell. Detecting DNA main Quantification of nucleic acids A diphenylamine DPA indicator will confirm the presence of DNA. This procedure involves chemical hydrolysis of DNA when heated e.g. 95 C in acid, the reaction requires a deoxyribose sugar and therefore is specific for DNA. Under these conditions, the 2 deoxyribose ... a blue colored compound. DNA concentration can be determined measuring the intensity of absorbance ... DNA concentrations. Measuring the intensity of absorbance of the DNA solution at wavelengths Quantification of nucleic acids 260 nm and 280 nm is used as a measure of DNA purity. DNA absorbs UV ... of DNA has the 260 280 ratio at 1.8 and is relatively free from protein contamination. A DNA preparation that is contaminated with protein will have a 260 280 ratio lower than 1.8. DNA can be quantified ... more details
Unreferenced date December 2009 Extrachromosomal DNA sometimes called extranuclear DNA or nonchromosomal DNA is DNA located or maintained in a cell biology cell apart from the chromosomes . In many cases, extrachromosomal DNA is contained in cytoplasmic organelles , such as mitochondria most eukaryotes , and in chloroplast s and plastid s plants . Extrachromosomal DNA can also be found in the plasmids of bacteria , or in intracellular parasitism parasites such as virus es. Certain types of cells such as cancer cells and cells maintained in cell culture artificial culture are known to acquire extrachromosomal DNA which provides them a selective advantage for growth under specific conditions. One example being the extrachromosomal double minute s which have been shown to contain oncogenes and provide growth enhancement in certain cancers. Extrachromosomal DNA sometimes contains addiction module s, a system that mediates cell death . DEFAULTSORT Extrachromosomal Dna Category DNA ur ... more details
Linker DNA is double stranded DNA in between two nucleosome cores that, in association with histone H1 , holds the cores together. Linker DNA is seen as the string in the beads and string model, which is made by using an ionic solution on the chromatin. Linker DNA connects to histone H1 and histone H1 sits on the nucleosome core. Nucleosome is technically the consolidation of a nucleosome core and one adjacent linker DNA however, the term nucleosome is used freely for solely the core. Linker DNA may be degraded by endonuclease s. ref Molecular Biology of The Cell, Fifth Edition, Alberts et. al, Garland Science, 2008 ref References reflist External links http www.ncbi.nlm.nih.gov bookshelf br.fcgi?book mboc4&part A632&rendertype figure&id A632 Image illustrating linker DNA Category DNA Category DNA binding proteins Category Electrochemistry de Linker DNA ... more details
Satellite DNA consists of very large arrays of tandemly arrayed genes tandemly repeating, non coding DNA . Satellite DNA is the main component of functional centromeres , and form the main structural constituent of heterochromatin . ref cite book author Knight, Julian C. title Human Genetic Diversity Functional Consequences for Health and Disease publisher Oxford University Press year 2009 isbn 9780199227693 ... 000031999 satellite DNA ref The name satellite DNA refers to how repetitions of a short DNA sequence ... , and thus have a different density from bulk DNA such that they form a second or satellite band when genomic DNA is separated on a Density Gradient density gradient . citation needed date January 2011 Types of satellite DNA Satellite DNA, together with minisatellite and Microsatellite genetics microsatellite DNA, constitute the tandem repeats . ref MeshName Tandem Repeat ref Some types of satellite DNA in humans are class wikitable Type Size of repeat unit bp Location alphoid DNA 171 All chromosomes ... 3 5 Most chromosomes Length A repeated DNA motif pattern can be between 1 base pair long a mononucleotide repeat to several thousand base pairs long, and the total size of a satellite DNA block can be several megabases without interruption. Most satellite DNA is localized to the telomeric or the centromeric ... DNA is a short region 1 5kb of 20 50 repeats. The difference in how many of the repeats is present in the region length of the region is the basis for DNA fingerprinting . citation needed date January 2011 Origin Satellite DNA, at least the microsatellite variety, is thought to have originated by slippage ... book author Beridze, Thengiz title Satellite DNA publisher Springer Verlag year 1986 isbn 978 0387158761 ... books?id MPkwi i33zYC&pg PA53 External links MeshName Satellite DNA Repeated sequence DEFAULTSORT Satellite Dna Category Repetitive DNA sequences de Satelliten DNA fr ADN satellite he DNA it DNA satellite sv Satellit DNA tr Satelit DNA ... more details
Unreferenced stub auto yes date December 2009 Orphan date December 2009 Spacer DNA are regions of non transcribed DNA between tandemly repeated gene s, such as ribosomal RNA genes in eukaryote s. Its function most likely involves ensuring the high rates of transcription associated with these genes. In bacteria, spacer DNA sequences are only a few nucleotides long. In eukaryotes, they can be extensive and include repetitive DNA, comprising the majority of the DNA of the genome. The term is used particularly for the spacer DNA between the many tandemly repeated copies of the ribosomal RNA genes. DEFAULTSORT Spacer Dna Category Genetics Genetics stub ... more details
DNA Oy is a Finnish on telecommunications company. It was born in 2007 after a merger. DNA offers cellular phone services, ADSL , cable television and regular telephone service. DNA was originally founded as the cell phone operator of the Finnet group of current and former telephone cooperative s after there was a splitup in the association. The Helsinki Telephone Association now Elisa Oyj left Finnet and they needed to found an own operator, which they did in 2000. In 2006 there began to be new difficulties between the remaining Finnet companies. The largest members merged themselves with DNA and left the association. External links http www.dna.fi DNA s website Finnishmobileoperators fi Dna yritys sv DNA Finland ... more details
Infobox journal title DNA Research cover File DNA Research cover.gif editor Michio Oishi discipline Genomics language English language English abbreviation DNA Res. publisher Kazusa DNA Research Institute Universal Academy Press country Japan frequency 6 year history 1994 present openaccess Yes license impact 3.612 impact year 2008 website http dnaresearch.oxfordjournals.org link1 link1 name link2 link2 name RSS http dnaresearch.oxfordjournals.org rss current.xml atom JSTOR OCLC 30467755 LCCN QH426 CODEN DARSE8 ISSN 1340 2838 eISSN 1756 1663 boxwidth DNA Research is an international, peer review ed journal of genomics and DNA research. DEFAULTSORT Dna Research Journal Category Genetics journals Category Genetics literature Category Publications established in 1994 Sci journal stub ... more details
to generate a nationwide DNAdatabase called the FBI Combined DNA Index System CODIS . ref http www.cstl.nist.gov biotech strbase images STRBase.pdf ref In addition to these 13 STR markers, DNA Tribes ...Infobox Company name DNA Tribes type Privately held company Private headquarters Virginia United States ... DNATribes.com DNA Tribes is a personal genomics and biotechnology company based in Arlington, Virginia ref name SFGATE Several companies, including DNA Tribes of Arlington, Va., also offer a test that examines the DNA contribution of both parents. These tests are the most controversial because ... cgi bin article.cgi?f c a 2007 12 02 MNPQTIG6U.DTL title DNA ancestry testing leaves some in doubt ... genetic markers developed by the FBI for individual identification in a forensic context. DNA Tribes ... DNA test Biogeographical ancestry Autosomal DNA is inherited from both maternal and paternal ancestors ... name sfg Companies like DNA Tribes and DNAPrint are offering DNA marker tests by mail cite web url ... bounty are start up testing companies with names like DNA Tribes and Ethnoancestry. cite news url http www.nytimes.com 2006 04 12 us 12genes.html? r 1&scp 1&sq DNA 20Tribes&st cse title Seeking Ancestry in DNA Ties Uncovered by Tests last Harmon first Amy date 2006 04 12 publisher The New York Times accessdate 2009 05 12 ref Scientific basis DNA Tribes proprietary analysis has been developed ... faq Genetic markers STR DNA Tribes uses a type of autosomal STR genetic markers developed by the FBI for individual identification. Using this system, each person s DNA profile serves as a genetic fingerprint ... testing. DNA Tribes uses this highly unique autosomal STR genetic profile to measure a person s genetic ... to each person, they allow DNA Tribes proprietary identification of the most detailed map of world genetic regions performed to date. ref name faq SNP DNA Tribes also provides since 2011 a geographical ... microarray tests. The report includes both admixture and total similarity comparisons of one s DNA ... more details
Image Ti plasmid.svg thumb 350px right Ti plasmid with T DNA region The transfer DNA abbreviated T DNA is the transferred deoxyribonucleic acid DNA of the Ti plasmid tumor inducing Ti plasmid of some species of bacteria such as Agrobacterium tumefaciens and Agrobacterium rhizogenes . It derives its name from the fact that the bacterium transfers this DNA fragment into the host plant s cell nucleus nuclear DNA genome . The T DNA is bordered by 25 base pair repeats on each end. Transfer is initiated .... The bacterial T DNA is about 20,000 base pairs long and contains gene s that code for enzyme s synthesizing opines and phytohormone s. By transferring the T DNA into the plant genome, the bacterium ... are amino acid derivatives used by the bacterium as a source of carbon and energy. T DNA transformation Agrobacterium mediated T DNA transfer is widely used as a tool in biotechnology . In genetic engineering , the tumor promoting and opine synthesis genes are removed from the T DNA and replaced ... of glutamine synthetase . Agrobacterium is then used as a vector to transfer the engineered T DNA ... transgenic plant s carrying a foreign gene. Mechanism of T DNA Transformation The first step in integrating the T DNA into a host genome is the formation of nick at the right border of the Ti plasmid. This nick creates a region of single stranded DNA from the left border of the T DNA gene over to the right ... DNA. DNA synthesis will displace the single stranded region and then a second nick at the left border region will release the single stranded T DNA fragment. This fragment can then be incorporated into a host genome. T DNA mutagenesis The same procedure of T DNA transfer can be used to disrupt genes via insertional mutagenesis . Not only does the inserted T DNA sequence create a mutation but it also ..., ISBN 0 7167 1007 2 DEFAULTSORT T Dna Category Biotechnology Category Plant pathogens and diseases Category Mobile genetic elements biotech stub botany stub genetics stub fr ADN T pl T DNA sv T DNA ... more details
unreferenced date February 2011 A nick is a discontinuity in a double stranded DNA molecule where there is no phosphodiester bond between adjacent nucleotide s of one DNA Overview of molecular structure strand typically through damage or enzyme action. Nick allows for much needed release of torsion in the strand. See also Phosphodiester bond DEFAULTSORT Nick Dna Category DNA Genetics stub ... more details
Windows DNA is short for Windows Distributed interNet Applications Architecture , a marketing name for a collection of Microsoft technologies that enable the Microsoft Windows Windows platform and the Internet to work together. Some of the principal technologies comprising DNA include ActiveX , Dynamic HTML DHTML and Component Object Model COM . Windows DNA has been largely superseded by the Microsoft .NET Framework , and Microsoft no longer uses the term. To support web based application Microsoft has tried to add internet features into the operating system using COM. But developing a web based application using COM based Windows DNA is quite complex. The complexity is due to the simple fact that Windows DNA requires the use of numerous technologies and languages. These technologies are completely unrelated from a syntactic point of view. External links http www.smartcomputing.com editorial dictionary detail.asp?&searchtype 1&reftype Encyclopedia&DicID 19618 Windows DNA at Smart Computing Encyclopedia microsoft stub Category Windows communication and services ru Windows DNA zh Windows DNA ... more details
infobox enzyme Name DNA directed DNA polymerase EC number 2.7.7.7 CAS number 9012 90 2 IUBMB EC number 2 7 7 7 GO code 0034061 image DNA polymerase.png width 260px caption 3D structure of the DNA binding helix turn helix motifs in human DNA polymerase beta based on pdb file http www.rcsb.org pdb explore.do?structureId 7ICG 7ICG A DNA polymerase is an enzyme the suffix ase is used to identify enzymes that helps catalyze in the polymerization of deoxyribonucleotide s into a DNA strand. DNA polymerases are best known for their Negative feedback feedback role in DNA replication , in which the polymerase reads an intact DNA strand as a wikt template template and uses it to synthesize the new strand. This process copies a piece of DNA. The newly polymerized molecule is complementary to the template strand and identical to the template s original partner strand. DNA polymerases use magnesium ions as Cofactor biochemistry cofactors . Human DNA polymerases are 900 1000 amino acids long. Function Image DNA polymerase.svg thumb 200px right DNA polymerase with proofreading ability DNA polymerase ... strand in a 5 3 direction. No known DNA polymerase is able to begin a new chain de novo . DNA ... and or DNA bases. In DNA replication, the first two bases are always RNA, and are synthesized by another enzyme called primase . An enzyme known as a helicase is required to unwind DNA from a double ... with the semiconservative model of DNA replication. Error correction is a property of some, but not all, DNA polymerases. This process corrects mistakes in newly synthesized DNA. When an incorrect base pair is recognized, DNA polymerase reverses its direction by one base pair of DNA. The 3 5 exonuclease ... base and replication can continue. Various DNA polymerases are extensively used in molecular biology experiments. Variation across species DNA polymerases have highly conserved structure, which means ... provides evolutionary advantages. Some viruses also encode special DNA polymerases, such as Hepatitis ... more details
DNA gyrase , often referred to simply as gyrase , is an enzyme that relieves strain while double stranded DNA is being unwound by helicase . This causes negative supercoiling of the DNA. Bacteria l DNA .... DNA gyrase is a type II topoisomerase EC number 5.99.1.3 that introduces negative supercoil s or relaxes positive supercoils into DNA by looping the template so as to form a crossing, then cutting ... , whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each ... negative supercoils into DNA is what allows bacterial DNA to have free negative supercoils. The ability of gyrase to relax positive supercoils comes into play during DNA replication . The right handed nature of the DNA double helix causes positive supercoils to accumulate ahead of a translocating enzyme, in the case of DNA replication, a DNA polymerase . The ability of gyrase and topoisomerase IV ... pubmed docsum Mechanochemical Analysis of DNA Gyrase Using Rotor Bead Tracking , Nature 2006 Jan 5 Vol. 439 100 104. ref has characterized gyrase activity as a function of DNA tension applied force and Adenosine triphosphate ATP , and proposed a mechanochemical model. Upon binding to DNA the Gyrase DNA state , there is a competition between DNA wrapping and dissociation, where increasing DNA ... work by competitive inhibition of energy transduction of DNA gyrase by binding to the ATPase active ... bind these enzymes and prevent them from decatenating replicating DNA. Quinolone resistant bacteria frequently harbor mutated topoisomerases that resist quinolone binding. Notes reflist DNA ... carries out nicking of DNA,B subunit introduces negative supercoils,and then A subunit reseals the strands.Fluorquinolones .... References Molecular Cloning of Apicoplast Targeted Plasmodium falciparum DNA Gyrase Genes Unique ..., Mar. 2007, p. 398 412 Topoisomerases DNA replication Category DNA Category EC 5.99.1 Category Enzymes de Gyrase es ADN girasa fr ADN gyrase it DNA girasi ja DNA pl Gyraza DNA zh DNA ... more details
Unreferenced stub auto yes date December 2009 A DNA construct is an artificially constructed segment of nucleic acid that is going to be transplanted into a target Biological tissue tissue or Cell biology cell . It often contains a DNA insert, which contains the gene sequence encoding a protein of interest, that has been subcloned into a Vector molecular biology vector , which contains bacterial resistance genes for growth in bacteria , and Promoter biology promoter s for expression in the organism. A DNA construct may express wildtype protein, prevent the expression of certain genes by expressing competitors or inhibitors, or express mutant proteins, such as deletion mutations or missense mutation s. A DNA construct is often used in molecular biology to analyze macromolecules such as proteins or RNA in more detail. See also Rescue construct Disruption construct DEFAULTSORT Dna Construct Category DNA Biochem stub simple DNA construct ... more details
A DNA machine is a molecular machine constructed from DNA . Research into DNA machines was pioneered in the late 1980s by Nadrian Seeman and co workers from New York University . DNA is used because of the numerous biological tools already found in nature that can affect DNA, and the immense knowledge of how DNA works previously researched by biochemistry biochemists . DNA machines can be logically designed since DNA assembly of the double helix is based on strict rules of base pairing that allow portions of the strand to be predictably connected based on their sequence. This selective stickiness is a key advantage in the construction of DNA machines. An example of a DNA machine was reported by Bernard Yurke and co workers at Lucent Technologies in the year 2000, who constructed molecular tweezers out of DNA. ref name pmid10949296 cite journal author Yurke B, Turberfield AJ, Mills AP, Simmel FC, Neumann JL title A DNA fuelled molecular machine made of DNA journal Nature volume 406 issue 6796 pages 605 8 year 2000 month August pmid 10949296 doi 10.1038 35020524 url ref The DNA tweezers contain three strands A, B and C. Strand A latches onto half of strand B and half of strand C, and so it joins them all together. Strand A acts as a hinge so that the two arms &mdash AB and AC &mdash can move. The structure floats with its arms open wide. They can be pulled shut by adding a fourth strand of DNA D programmed to stick to both of the dangling, unpaired sections of strands B and C. The closing of the tweezers was proven by tagging strand A at either end with light emitting molecules ... BAC, so float away. The DNA machine can be opened and closed repeatedly by cycling between strands ... a self assembled DNA tetrahedron . The state of the device can be determined by measuring the separation ... reflist See also DNA nanotechnology Category DNA nanotechnology Category Molecular machines sci stub ar it Macchina di DNA ru tr DNA makinalar ... more details
Not to be confused with the book The Selfish Gene . Selfish DNA refers to those sequences of DNA which, in their purest form, have two distinct properties 1 the DNA sequence spreads by forming additional copies of itself within the genome and 2 it makes no specific contribution to the reproductive success of its host organism . This idea was sketched briefly by Richard Dawkins in his 1976 book The Selfish Gene and was explicitly exposed in two 1980 articles in Nature magazine. According to one of these articles quotation The theory of natural selection, in its more general formulation, deals with the competition between replicating entities. It shows that, in such a competition, the more efficient replicators increase in number at the expense of their less efficient competitors. After a sufficient time, only the most efficient replicators survive. L.E. Orgel & F.H.C. Crick Selfish DNA the ultimate parasite The selfish DNA can be considered an efficient replicator that follows another way of increasing in number. Examples Transposon s copy themselves to different locus genetics loci inside the genome. These elements constitute a large fraction of eukaryotic genome size s C value s about 45 of the human genome is composed of transposons and their defunct remnants. Homing endonuclease gene s cleave DNA at its own site on the homologous chromosome , triggering the DNA repair Double strand breaks DNA double stranded break repair system, which repairs the break by copying the HEG onto the homologous chromosome. HEGs have been characterized in yeast , and can only survive by passing between multiple isolated populations or species. Supernumerary B chromosome s are essential chromosomes that are transmitted in higher than expected frequencies, which leads to their accumulation in progenies ... & Crick , F.H.C. 1980 Selfish DNA the ultimate parasite. Nature, 284, 604 607. Category DNA Category Selection he DNA pl Samolubny DNA zh DNA ... more details
DNA shuffling is a way to rapidly propagate beneficial mutation s in a directed evolution experiment. It is used to rapidly increase DNA library size. ref cite journal last Cohen first J. title How DNA Shuffling Works journal Science volume 293 issue 5528 pages 237 237 doi 10.1126 science.293.5528.237 accessdate 8 May 2011 ref Procedure DNAse is firstly used to fragment a set of parent gene s into pieces of 50 100 base pair bp in length. This is then followed by a polymerase chain reaction PCR without primers DNA fragments with sufficient overlapping homologous sequence will anneal to each other and are then extended by DNA polymerase . Several rounds of this PCR extension are allowed to occur, after some of the DNA molecules reach the size of the parental genes. These genes can then be amplified with another PCR, this time with the addition of Primer molecular biology primers that are designed to complement the ends of the strands. The primers may have additional sequences added to their 5 ends, such as sequences for restriction enzyme recognition sites needed for ligation into a cloning vector. It is possible to recombination recombine portion of these genes to generate hybrids or Chimera genetics chimeric forms with unique properties, this is called DNA shuffling. Shuffling methods Using restriction enzymes Restriction enzyme s that cut in similar places are used to digest members of the gene family DNA fragments are joined together with DNA ligase Large numbers of hybrid biology hybrids are produced which can be tested for unique properties Using DNAse 1 Different members of the gene family are fragmented using DNAse 1 followed by PCR During PCR different members of the family are cross primed, DNA fragments with high homology biology homology will anneal to each other The generated hybrids are then used to generate a DNA library library of mutants which are tested ... references DEFAULTSORT Dna Shuffling Category DNA es Barajado de ADN ... more details
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