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
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
Refimprove date February 2007 enzyme Name DNA ligase EC number 6.5.1.1 CAS number 9015 85 4 IUBMB EC number 6 5 1 1 GO code 0003910 image DNA Repair.jpg width caption DNA ligase repairing chromosomal damage protein Name ligase I, DNA, ATP dependent caption image DNA Ligase.jpg width 200 HGNCid 6598 Symbol ... 19 Arm Band LocusSupplementaryData protein Name ligase III, DNA, ATP dependent caption image width ... PDB ECnumber Chromosome 17 Arm q Band 11.2 LocusSupplementaryData q12 protein Name ligase IV, DNA, ATP ... biology , DNA ligase is a specific type of enzyme, a ligase , EC number 6.5.1.1 that repairs single stranded discontinuities in double stranded DNA molecules, in simple words strands that have double strand break a break in both complementary strands of DNA . Purified DNA ligase is used in gene cloning to join DNA molecules together. The alternative, a single strand break, is fixed by a different type of DNA ligase using the Complementary DNA complementary strand as a template, ref name pmid15565146 cite journal pages 473 8 doi 10.1038 nature03082 title Human DNA ligase I completely encircles and partially unwinds nicked DNA year 2004 last1 Pascal first1 John M. last2 O Brien first2 ... 7016 pmid 15565146 ref but still requires DNA ligase to create the final phosphodiester bond to fully repair the DNA. DNA ligase has applications in both DNA repair and DNA replication see DNA ligase Mammalian ligases Mammalian ligases . In addition, DNA ligase has extensive use in molecular biology laboratories for Genetic recombination experiments see DNA ligase Applications in molecular biology research Applications in molecular biology research . Ligase mechanism The mechanism of DNA ligase ... science.186.4166.790 title DNA Ligase Structure, Mechanism, and Function year 1974 last1 Lehnman first1 ... 2 A pictorial example of how a ligase works with DNA end sticky end s Ligase will also work with DNA .... Mammalian ligases This section is linked from DNA ligase In mammals, there are four specific ... more details
In molecular genetics , a DNA adduct is a piece of DNA covalent bond covalently bonded to a cancer causing chemical. This process could be the start of a cancerous cell, or carcinogenesis . DNA adducts in scientific experiments are used as biomarker s of exposure ref cite journal last La first DK coauthors Swenberg, JA title DNA adducts biological markers of exposure and potential applications to risk assessment. journal Mutation Research Reviews in Genetic Toxicology year 1996 volume 365 issue 1 3 pages 129 146 ref and as such are themselves measured to reflect quantitatively, for comparison, the amount of carcinogen exposure to the subject organism, i.e. rats or other living animals. Citation needed date October 2010 Under experimental conditions for study, such DNA adducts are induced by known carcinogen s, of which commonly used is DMBA 7,12 dimethylbenz a anthracene . For example, the term DMBA DNA adduct in a scientific journal refers to a piece of DNA that has DMBA attached to it. The presence of such an adduct indicates prior exposure to a potential carcinogen, but does not by itself indicate the presence of cancer in the subject animal ref cite web last Farmer first P title Biomarkers of exposure and effect for environmental carcinogens, and their applicability to human molecular ... needed date October 2010 Examples Chemicals which form DNA adducts include acetaldehyde , is a significant constituent of tobacco smoke cisplatin binds to DNA and causes crosslinking, leading to death ... DNA damage by malondialdehyde. Marnett LJ. ref DNA adducts include etheno DNA adducts 1,N 6 etheno ... 1 sub G , a by product of base excision repair BER of a specific type of DNA adduct called M1dG. DNA Damage When a chemical binds to DNA, the DNA becomes damaged, and proper and complete replication cannot ..., and without proper DNA repair DNA repair happens naturally under normal circumstances , this can lead ... DEFAULTSORT Dna Adduct Category Oncology genetics stub ru tr DNA kat m ... more details
Merge from Replication fork discuss Talk DNA replication Merge from Replication fork date May 2009 Image DNA replication split.svg thumb 200px right DNA replication. The double helix is unwound and each ... partner strands. DNA replication is a biological process that occurs in all life on Earth living organisms and copies their DNA it is the basis for heredity biological inheritance . The process starts when one double stranded DNA molecule produces two identical copies of the molecule. The cell cycle mitosis also pertains to the DNA replication reproduction process. The cell cycle includes, interphase, prophase, metaphase, anaphase, and telophase. Each strand of the original double stranded DNA ... ensure Mutation near perfect fidelity for DNA replication. ref cite book author Berg JM, Tymoczko ... 0 7167 3051 0 http www.ncbi.nlm.nih.gov books bv.fc,kgi?rid stryer.chapter.3740 Chapter 27 DNA Replication ... 3218 1 http www.ncbi.nlm.nih.gov books bv.fcgi?rid mboc4.chapter.747 Chapter 5 DNA Replication, Repair, and Recombination ref In a cell biology cell , DNA replication begins at specific locations in the genome ... 4 DNA Replication of Both Strands Proceeds Rapidly from Specific Start Sites ref Unwinding of DNA at the origin, and synthesis of new strands, forms a replication fork . In addition to DNA polymerase , the enzyme that synthesizes the new DNA by adding nucleotides matched to the template strand, a number ... of DNA synthesis. DNA replication can also be performed in vitro artificially, outside a cell . DNA polymerases , isolated from cells, and artificial DNA primers are used to initiate DNA synthesis at known ..., employs such artificial synthesis in a cyclic manner to amplify a specific target DNA fragment from a pool of DNA. DNA structure DNA usually exists as a double stranded structure, with both strands coiled together to form the characteristic double helix . Each single strand of DNA is a chain ... backbone of the DNA double helix with the bases pointing inward. Nucleotides bases are matched between ... more details
DNA footprinting is a method of investigating the sequence specificity of DNA binding proteins in vitro. This technique can be used to study protein DNA interactions both outside and within cells. The regulation ... promoters , enhancers , or Silencer DNA silencers to drive or repress transcription are fundamental to understanding the unique regulation of individual genes within the genome . Techniques like DNA footprinting will help elucidate which proteins bind to these regions of DNA and unravel the complexities of transcriptional control. Method Image Courtney 2008.jpg thumb center 550px Figure 1. DNA footprinting ... binds to a region of interest within a DNA molecule. The wet lab methodology is summarized, with appropriate ... of DNA binding ligands. Methods. 42 128 140. ref Polymerase chain reaction PCR amplify and label ... 50 to 200 base pairs in length. Add protein of interest to a portion of the labeled template DNA ... portions of DNA template. The cleavage agent is a chemical or enzyme that will cut at random locations in a sequence independent manner. The reaction should occur just long enough to cut each DNA molecule in only one location. A protein that specifically binds a region within the DNA template will protect the DNA it is bound to from the cleavage agent. Run both samples side by side on a polyacrylamide gel electrophoresis . The portion of DNA template without protein will be cut at random locations, and thus when it is run on a gel, will produce a ladder like distribution. The DNA template with the protein will result in ladder distribution with a break in it, the footprint , where the DNA has been protected from the cleavage agent. Note Maxam Gilbert chemical DNA sequencing can be run alongside ... binding site. Labeling The DNA template can be labeled at the 3 or 5 end, depending on the location ... DNA fragments for footprinting analysis, as the method was originally developed from the Maxam Gilbert ... small amounts of DNA. Fluorescence is a desirable advancement due to the hazards of using radio ... more details
Refimprove date December 2009 File DNA Sequencers from Flickr 57080968.jpg thumb right DNA sequencers A DNA sequencer is a scientific instrument used to automate the DNA sequencing process. It can be also considered an optical instrument as it generally analyzes light signals originating from fluorochrome s attached to nucleotides. Modern automated DNA sequencing instruments called DNA sequencers are able to sequence multiple samples in a batch run and perform as many as 24 runs a day. These perform only the size separation and peak reading the actual sequencing reaction s , cleanup and resuspension in a suitable buffer must be performed separately. The magnitude of the fluorescent signal is related to the number of strands of DNA that are in the reaction. If the initial amount of DNA is small, the signals will be weak. However, the properties of PCR allow one to increase the signal by increasing the number of cycles in the PCR program. A simple DNA sequencer will have one or more lasers that emit at a wavelength that is absorbed by the fluorescent dye that has been attached to the DNA strand of interest. It will then have one or more optical detectors that can detect at the wavelength that the dye fluoresces at. The presence or absence of a strand of DNA is then detected by monitoring the output of the detector. Since shorter strands of DNA move through the gel matrix faster they are detected sooner and there is then a direct correlation between length of DNA strand and time at the detector. This relationship is then used to determine the actual DNA sequence. The output of these machines is not perfect as it may contain reading errors and needs to be processed see Sequence ..., today, modern software can automatically process the output in seconds. Other Applications DNA ... laboratories, suggests that DNA sequencers may be used to study temperature dependent events ... Dna Sequencer Category Scientific instruments Category Molecular biology Category DNA sequencing ... more details
DNA Bioscience is a DNA testing company offering a DNA Parental testing paternity testing service in the UK. The company gained much press in 2005 when the UK politician David Blunkett bought shares in the company, shortly after which he became Secretary of State for Work and Pensions . He failed to declare his interest in the company, which ultimately led to his resignation from Cabinet of the United Kingdom the Cabinet in November 2005. ref Antony Barnett and Tania Branigan http business.guardian.co.uk story 0,,1663483,00.html DNA company that Blunkett backed heads for collapse , The Guardian , 9 December 2005 ref The company went into liquidation on 8 December 2005 ref Rosie Murray West http www.telegraph.co.uk news main.jhtml?xml news 2005 12 10 nblunk10.xml&sSheet portal 2005 12 10 ixportal.html Blunkett could lose 15,000 as DNA company faces insolvency , Daily Telegraph , 10 December 2005 ref ref Antony Barnett and Tania Branigan http business.guardian.co.uk story 0,,1663483,00.html DNA company that Blunkett backed heads for collapse , The Guardian , 9 December 2005 ref and was bought by an American based DNA testing laboratory. ref http www.timesonline.co.uk newspaper 0,,175 1918531,00.html Debts force Blunkett DNA test company to halt trading , The Times , 12 December 2005 subscription needed ref References reflist External links http www.dna bioscience.co.uk Company website Category Biotechnology companies of the United Kingdom med company stub ... more details
File Apoptotic DNA Laddering.png alt White DNA bands against a dark grey background, resembling the rungs of a ladder thumb right upright DNA laddering left visualised in an agarose gel by ethidium bromide staining. A Base pair Length measurements 1 kb DNA ladder marker middle and Scientific control control DNA right are included. DNA laddering is a phenomenon seen in laboratory tests it is a sensitive indicator of programmed cell death , specifically of apoptosis . It was first described in 1980 by Andrew Wyllie at the University of Edinburgh Medical School . ref cite journal author Wyllie AH date 1980 04 10 title Glucocorticoid induced thymocyte apoptosis is associated with endogenous endonuclease activation journal Nature journal Nature volume 284 issue 5756 pages 555 556 issn 0028 0836 doi 10.1038 284555a0 pmid 6245367 url http www.nature.com nature journal v284 n5756 abs 284555a0.html ref Endonuclease activation is a characteristic feature of apoptosis. This degrades genomic DNA at internucleosomal linker regions and produces 180 to 185 base pair DNA fragments. On Agarose gel electrophoresis , these give a characteristic laddered appearance. The dying cell s Morphology biology morphological changes are short lived and difficult to detect. DNA laddering has therefore become a sensitive method to distinguish apoptosis from Ischemia ischemic or necrosis toxic cell death . ref cite journal author Iwata M, Myerson D, Torok Storb B, Zager RA. year 1994 month December title An evaluation of renal tubular DNA laddering in response to oxygen deprivation and oxidant injury journal Journal of the American Society of Nephrology volume 5 issue 6 pages 1307 1313 issn 1046 6673 doi pmid 7893995 url http jasn.asnjournals.org cgi content abstract 5 6 1307 ref References reflist www.chemeurope.com See also Apoptotic DNA fragmentation Caspase activated DNase Nicoletti assay TUNEL assay Category Apoptosis Category Biological techniques and tools Category Cell biology Category Electrophoresis ... more details
Image Z DNA orbit animated small.gif right frame The Z DNA structure. Proteopedia Z DNA Z DNA is one of the many possible double helical structures of DNA . It is a left handed double helical structure ... common B DNA form . Z DNA is thought to be one of three biologically active double helical structures along with A DNA A and B DNA. History Z DNA was the first single crystal X ray structure of a DNA fragment a self complementary DNA hexamer d CG sub 3 sub . It was resolved as a left handed double ... double helical DNA fragment at atomic resolution journal Nature London volume 282 pages 680 686 year ... of a B to Z DNA junction in 2005 ref name Ha2005 cite journal author Ha SC, Lowenhaupt K, Rich A, Kim YG, Kim KK title Crystal structure of a junction between B DNA and Z DNA reveals two extruded bases ... bibcode 2005Natur.437.1183H ref provided a better understanding of the potential role Z DNA plays in cells. Whenever a segment of Z DNA forms, there must be B Z junctions at its two ends, interfacing it to the B form of DNA found in the rest of the genome . In 2007, the RNA version of Z DNA, Z ... pmid 6482970 doi 10.1038 311584a0 ref Structure Image B , Z DNA junction 2ACJ.png right thumb B Z DNA junction bound to a Z DNA binding domain. Note the two highlighted extruded bases. From PDB 2ACJ . Z DNA is quite different from the right handed forms. In fact, Z DNA is often compared against B DNA in order to illustrate the major differences. The Z DNA helix is left handed and has a structure that repeats every 2 base pairs. The major and minor grooves, unlike A and B DNA, show little difference ... DNA supercoil ing or high salt and some cation s all at physiological temperature, 37 C, and pH 7.3 7.4 . Z DNA can form a junction with B DNA called a B to Z junction box in a structure which involves ... two Z DNA helices journal Proc Natl Acad Sci USA date 2010 05 18 volume 107 issue 20 pages 9088 9092 pmid 20439751 pmc 2889044 doi 10.1073 pnas.1003182107 ref The Z DNA conformation has been difficult ... more details
DNA origami is the nanoscale folding of DNA to create arbitrary two and three dimensional shapes at the nanoscale . The specificity of the interactions between Complementarity molecular biology complementary base pairs make DNA a useful construction material, through design of its base sequences. Developed by Paul Rothemund at the California Institute of Technology , the process involves the folding of a long single strand of virus viral DNA aided by multiple smaller staple strands. These shorter strands bind the longer in various places, resulting in various shapes, including a smiley face and a coarse map of China and Americas the Americas , along with many three dimensional structures such as cubes. To produce a desired shape, images are drawn with a Raster graphics raster fill of a single long DNA molecule . This design is then fed into a computer program that calculates the placement of individual staple strands. Each staple binds to a specific region of the DNA template, and thus ... are known and displayed. The DNA is mixed, then heated and cooled. As the DNA cools, the various ..., including atomic force microscopy , or fluorescence microscopy when DNA is coupled to fluorescent ... self assembly of materials. Though DNA is not the natural choice for building active ... computing. DNA origami was the cover story of Nature journal Nature on March 16, 2006. See also DNA nanotechnology Molecular self assembly Folding home References cite journal last Rothemund first Paul W. K. authorlink Paul W. K. Rothemund year 2006 month title Folding DNA to create nanoscale ... DNA Tile Based Self Assembly Building Complex Nanoarchitectures year 2006 last1 Lin first1 Chenxiang ... issue 8 pages 1641 7 http news.bbc.co.uk 2 hi technology 8204906.stm DNA organises itself on silicon &ndash BBC News 2009 08 17 Category DNA nanotechnology Biochem stub nano tech stub ar de DNA Origami fr Origami ADN ... more details
Refimprove date February 2010 Image Circular DNA Supercoiling.png thumb right Supercoiled structure of circular DNA molecules with low writhe. Note that the helical nature of the DNA duplex is omitted for clarity. Image Linear DNA Supercoiling.png thumb right Supercoiled structure of linear DNA molecules with constrained ends. Note that the helical nature of the DNA duplex is omitted for clarity. DNA supercoiling refers to the over or under winding of a DNA strand, and is an expression of the strain ... DNA. Additionally, certain enzymes such as topoisomerases are able to change DNA topology to facilitate functions such as DNA replication or transcription. Mathematical expressions are used to describe supercoiling by comparing different coiled states to relaxed B form DNA. As a general rule, DNA ... of B DNA , the two strands twist around the helical axis once every 10.4 10.5 base pair s of DNA sequence sequence . Adding or subtracting twists, as some enzyme s can do, imposes strain. If a DNA segment ... freely, the circular DNA would contort into a new shape, such as a simple figure eight. Such a contortion ... DNA assumes to accommodate one too many or one too few helical twists. The two lobes of the figure ... of DNA topology . Instead, global contortions of a circular DNA, such as the rotation of the figure ... of twist and writhe. The twist is the number of helical turns in the DNA and the writhe is the number ... DNA topology. DNA of most organisms is negatively supercoiled. In part because chromosome s may ... an amount of writhe, just as if their ends were joined. Supercoiled DNA forms two structures a plectoneme or a toroid, or a combination of both. A negatively supercoiled DNA molecule will produce ... a branch point in the plectonemic structure. Occurrence of DNA supercoiling DNA supercoiling is important for DNA packaging within all cells. Because the length of DNA can be thousands of times that of a cell .... Supercoiling of DNA reduces the space and allows for much more DNA to be packaged. In prokaryotes ... more details
DNA Consultants is a DNA profiling company in Phoenix, Arizona , founded by Donald Panther Yates in 2003 ... one of the first papers on direct to the consumer genealogical DNA tests ref http ijd.cgpublisher.com product pub.29 prod.104 DNA Haplotyping and Diversity An Anthropogenealogical Method for Researching ... ref Peering Inward for Ethnic Identity, another general article on the intersection between DNA testing ... preview Peering Inward for Ethnic Identity Consumer Interpretation of DNA Test Results Identity ... and Consumer Cooperatives in the DNA Marketspace , ref http dnaconsultants.com LiteratureRetrieve.aspx ... Cooperatives in the DNA Marketspace ref the result of a long and extensive case study of the founding years of genetic genealogy companies such as Family Tree DNA and Oxford Ancestors at American ... formed by forums, listservs and end users. DNA Consultants has developed an autosomal DNA database for use in its in house studies and fulfillment of the direct to the consumer DNA tests it offers to the public ... of atDNA 4.0 contains data on 400 world populations representing over 115,000 anonymous subjects DNA profiling results from published forensic studies since 1996, when the Combined DNA Identification ... Detailed 336.html ref DNA Consultants has two ongoing DNA studies, a http dnaconsultants.com Cherokee index.htm Cherokee DNA Project under the administration of Holli S. Molnar and http dnaconsultants.com Melungeon index.htm Melungeon DNA Project under Phyllis Starnes. The company sells a range of consumer oriented DNA tests , many of which it has developed, not least its autosomal DNA profiling family of products, as well as older style Y chromosome and mitochondrial DNA tests. Native American, Jewish and Melungeon versions of its DNA Fingerprint Plus are available. For the DNA Fingerprint products, DNA Consultants uses Chromosomal Laboratories of Phoenix as its partner genomics ... affiliates servicecenter.html affiliated DNA testing centers . For other tests it works with other ... more details
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