Deoxyribose Nucleic Asid

DNA strand is made from alternating phospate and sugar residues. Thesre two strands run in opposite directions to each other and therefore antiparallel Attached to each sugar is one of four types of molecules called bases, The sugar in DNA is 2-deoxyribose which is apentose sugar searches of DNA into the related nuclear acid RNA in aproesss sugsrs are joined to phospate groups that from phosphodiester bonds between the third and forth carbon atoms adjacent sugar rings. DNA is a long polymer made from repeating units called nucleotides. The DNA is chain is 20-26 angstroms wide. DNA polymers can be very large molecules containing millions of nucleotides chemically with backbones made of sugars and phospates groups joined by ester bonds these on formation is using the genetic code....

Read more »

Genetic Disorder

Genetic disorder is a condition caused by abnormalities in genes or chromosomes. While some diseases such as cancer. Cancer are due to genetic abnormalities acquired in a few cells during life. The term "genetic disease" most commonly refers to diseases present in all cells of the body and present since conception. Some genetic disorders are caused by chromosomal abnormalities due to errors in meiosis, the process which produces reproductive cells such as sperm and eggs. Examples include Down syndrome. Turner Syndrome and Klinefelter's syndrome. Other genetic changes may occur during the production of germ cells by the parent. One example is the triplet expansion repeat mutations which can cause fragile X syndrome or Huntington's disease. Defective genes may also be inherited intact...

Read more »

Monoclonal Antibodies

Monoclonal antibodies are mono specific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cells. Given almost any substance. It is possible to create monoclonal antibodies that specifically bind to that substance, they can then serve to detect or purify that substance. This has become an important tool in biochemistry, molecular biology and medicine. When used as medications. the non-proprietary drug name ends in - m...

Read more »

Phyloge of DNA

Every living cells contains DNA, RNA and proteins. closely related organisms generally have degree of agreement in the molecular structure of these substances, Heterogeneous nuclear ribonucleic proteins are spliceosomal macromolecular assemblages and thus actively participate in pre - mRNA metabolism. Conserved sequences, such as mitochondrial DNA are expected to accumulate mutations over time and assuming a constant rate of mutation provide molecular interaction features. Molecular characterization of human hnRNP A3 showed that while the recombinant hnRNP A3 with its 296 amino acids migrates as excepted as 32 kDA protein on SDS-PAGE analysis, it is recognized by the patient's sear as a 50 kda highly related ye unknown cross reactive protein. The sequence comparision. however...

Read more »

Recombinant DNA

Recombinant DNA is a form of artificial DNA that is engineered through the combination of insertion of one or more DNA strands. Therefor combining DNA sequences that would not normally occur together. In terms of genetic modification, recombinant DNA is produced through the addition of relevant DNA into an existing organism genome, such as the plasmid of bacteria, to code for or alter different traits for a specific purpose, such as immunity. It differs from genetic recombination in that it does not occur through processes within the cell or ribosomes but is exclusively engineered.The Recombinant DNA technique was engineered by Stanley Norman Cohen and Herbert Boyer in 1973. They published their findings in a 1974 paper entitled Construction of Biologically Functional Bacterial...

Read more »

Deoxyribo Nucleic Acid (DNA)

Deoxyribo Nucleic Acid (DNA) is genetic material found in the cells of all living organisms. DNA is the fundamental building blocks for life. Nearly every cell (with a nucleus) in a person's body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but DNA can also found in the mitochondria (where it is called mitochondrial DNA or mtDNA).The information in DNA is made up four bases which combine to form chains. These bases include two purines (Adenine and Guanine) and two pyrimidines (Cytosine and Thymine). These are commonly referred to as A, G, C and T respectively. Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. It is the order, or sequence, of these bases which determines...

Read more »

DNA Double Helix

DNA is shown in the double stranded helical model for the graphic on the left. The easiest way to visualize DNA is an immensely long rope ladder, twisted into a cork-screw shape. The sides of the ladder are alternating sequences of deoxyribose and phosphate (backbone) while the rungs of the ladder (bases) are made in two parts with each part firmly attached to the side of the ladder. The parts in the rung are heterocyclic amines held in position by hydrogen bonding. Although most DNA exists as open ended double helices, some bacterial DNA has been found a cyclic helix. Occasionally, DNA has been found as a single stra...

Read more »

Forensic Testing for DNA

There are two main types of forensic DNA testing Called, RFLP and PCR based testing, although these terms are not very descriptive. Generally RFLP testing requires larger amounts of DNA and DNA must be underrated. Crime-scene evidence that is old or that is present in small amounts is often unsuitable for RFLP test. Warm moist conditions may accelerate DNA degradation rendering it unsuitable for RFLP in relatively short period of time. PCR-based testing often requires less DNA than RFLP testing and the DNA may be partially degraded more so than is the case with RFLP. However, PCR still has sample size and degradation limitations that sometimes may under-appreciated. PCR-based tests are extremely sensitive to contaminating DNA at the crime scene and within the test laboratory....

Read more »

Gene Cloning and Analysis of DNA

Known world wide as the standard introductory test to this important and exciting area the fifth edition of Gene Cloning and DNA Analysis addresses new and growing area of research which retaining the philosophy of the previous edition. Assuming the reader has little prior knowledge of subject is important. The principles of the techniques used and their applications are all carefully laid out. With over 250 clearly presented two color illustrations. In addition to number of informative changes to the test throughout the book. The final four chapters have been significantly updated and extended to reflect the striking advances made in resent years in the application of gene cloning and DNA analysis in biotechnology. Extended chapter on agriculture including new material on glyphosate...

Read more »

Microarrays Application

DNA Microarray technology helps in the identification of new genes, know about their functioning and expression levels under different conditions. Disease diagnosis of DNA Microarray technology helps researchers learn more about different diseases such as heart diseases, mental illness, infectious disease and especially the study of cancer. Until recently, different types of cancer have been classified on the basis of the organs in which the tumors develop. Now, with the evolution of microarray technology, it will be possible for the researchers to further classify the types of cancer on the basis of the patterns of gene activity in tumor cells. This will tremendously help the pharmaceutical community to develop more effective drugs as the treatment strategies will be targeted directly...

Read more »

RNA data Sequences to DNA

Proteins are not the only substances that are synthesized directly from data within the DNA. Some forms of RNA are specialized and also have their formula encoded directly in digital DNA formulae. Not all types of RNA are temporary intermediate forms with their form depending on whatever DNA they are copying. There are certain forms of RNA that have a particular form that is the same across all individuals. Some of these special-purpose RNA forms are, tRNA - transfer RNA rRNA - ribosome RNA There are exactly 20 forms of tRNA one each transfer a particular amino acid. tRNA molecules contain about 75-80 bases. tRNA recognizes one of the 64 triplets and matches it one of the 20 amino acids. Since there are 20 tRNA types, and not 64, each tRNA molecule has to recognize more than one...

Read more »

Grooves in the DNA

Twin helical strands form the DNA backbone. Another double helix may be found by tracing the spaces or grooves, between the strands. These voids are adjacent to the base pairs and may provide a binding site. As the strands are not directly opposite each other, the grooves are unequally sized. One groove, the major groove is 22 Å wide and the other, the minor groove, is 12 Å wide. The narrowness of the minor groove means that the edges of the bases are more accessible in the major groove. As a result, proteins like transcription factors that can bind to specific sequences in double-stranded DNA usually make contacts to the sides of the bases exposed in the major groove. This situation varies in unusual conformations of DNA within the cell (see below), but the major and minor grooves...

Read more »

DNA Base Pairing

Each type of base on one strand forms a bond with just one type of base on the other strand.This is called complementary base pairing. Here, purines form hydrogen bonds to pyrimidines with A bonding only to T and C bonding only to G. This arrangement of two nucleotides binding together across the double helix is called a base pair. As hydrogen bonds are not covalent, they can be broken and rejoined relatively easily. The two strands of DNA in a double helix can therefore be pulled apart like a zipper, either by a mechanical force or high temperature. As a result of this complementarity, all the information in the double-stranded sequence of a DNA helix is duplicated on each strand, which is vital in DNA replication. Indeed, this reversible and specific interaction between complementary...

Read more »

Sense and Antisense

A DNA sequence is called sense if its sequence is the same as that of a messenger RNA copy that is translated into protein. The sequence on the opposite strand is called the antisense sequence. Both sense and antisense sequences can exist on different parts of the same strand of DNA (i.e. both strands contain both sense and antisense sequences). In both prokaryotes and eukaryotes, anti sense RNA sequences are produced, but the functions of these RNAs are not entirely clear. One proposal is that antisense RNAs are involved in regulating gene expression through RNA-RNA base pairing. A few DNA sequences in prokaryotes and eukaryotes, and more in plasmids and viruses, blur the distinction between sense and antisense strands by having overlapping genes. In these cases some DNA sequences...

Read more »

Alternate structures of DNA

DNA exists in many possible conformations that include A-DNA, B-DNA, and Z-DNA forms although, only B-DNA and Z-DNA have been directly observed in functional organisms. The conformation that DNA adopts depends on the hydration level DNA sequence, the amount and direction of supercooling chemical modifications of the bases, the type and concentration of metal ions, as well as the presence of polyamines in solution. The first published reports of A-DNA X-ray diffraction patterns and also B-DNA used analysis based on Patterson transforms that provided only a limited amount of structural information for oriented fibers of DNA. An alternate analysis was then proposed by Wilkins act. all in 1953, for the in vivo B-DNA X-ray diffraction/scattering patterns of highly hydrated DNA fibers...

Read more »

Quadruplex structutrs of DNA

At the ends of the linear chromosomes are specialized regions of DNA called telomeres. The main function of these regions is to allow the cell to replicate chromosome ends using the enzyme telomerase as the enzymes that normally replicate DNA cannot copy the extreme 3 ends of chromosomes. These specialized chromosome caps also help protect the DNA ends, and stop the DNA repair systems in the cell from treating them as damage to be corrected. In human cells, telomeres are usually lengths of single-stranded DNA containing several thousand repeats of a simple TTAGGG sequence. These guanine-rich sequences may stabilize chromosome ends by forming structures of stacked sets of four-base units, rather than the usual base pairs found in other DNA molecules. Here, four guanine bases form...

Read more »

Boilogical Funtions Of DNA

DNA usually occurs as linear chromosomes in eukaryotes and circular chromosomes in prokaryotes. The set of chromosomes in a cell makes up its genome. the human genome has approximately 3 billion base pairs of DNA arranged into 46 chromosomes. The information carried by DNA is held in the sequence of pieces of DNA called genes. Transmission of genetic information in genes is achieved via complementary base pairing. For example in transcription, when a cell uses the information in a gene, the DNA sequence is copied into a complementary RNA sequence through the attraction between the DNA and the correct RNA nucleotides. Usually this RNA copy is then used to make a matching protein sequence in a process called translation which depends on the same interaction between RNA nucleotides....

Read more »

Genomes and Genes

Genomic DNA is located in the cell nucleus of eukaryotes as well as small amounts in mitochondria and chloroplasts. In prokaryotes the DNA is held within an irregularly shaped body in the cytoplasm called the nucleoid. The genetic information in a genome is held within genes, and the complete set of this information in an organism is called its genotype. A gene is a unit of heredity and is a region of DNA that influences a particular characteristic in an organism. Genes contain an open reading frame that can be transcribed, as well as regulatory sequences such as promoters and enhancers, which control the transcription of the open reading frame. In many species, only a small fraction of the total sequence of the genome encodes protein. For example, only about 1.5% of the human...

Read more »

DNA Binding Proteins

Structural proteins that bind DNA are well-understood examples of non-specific DNA-protein interactions. Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. In eukaryotes this structure involves DNA binding to a complex of small basic proteins called histones while in prokaryotes multiple types of proteins are involved. The histones form a disk-shaped complex called a nucleosome which contains two complete turns of double-stranded DNA wrapped around its surface. These non-specific interactions are formed through basic residues in the histones making ionic bonds to the acidic sugar-phosphate backbone of the DNA, and are therefore largely independent of the base sequence. Chemical modifications...

Read more »

Translation and Transcription of DNA

A gene is a sequence of DNA that contains genetic information and can influence the phenotype of an organism. Within a gene, the sequence of bases along a DNA strand defines a messenger RNA sequence which then defines one or more protein sequences. The relationship between the nucleotide sequences of genes and the amino-acid sequences of proteins is determined by the rules of translation, known collectively as the genetic code. The genetic code consists of three letter words called codons formed from a sequence of three nucleotides (e.g. ACT, CAG, TTT). In transcription, the codons of a gene are copied into messenger RNA by RNA polymerase. This RNA copy is then decoded by a ribosome that reads the RNA sequence by base-pairing the messenger RNA to transfer RNA, which carries amino...

Read more »

Genatic Enginearing

Methods have been developed to purify DNA from organisms, such as phenol-chloroform extraction and manipulate it in the laboratory such as restriction digests and the polymerase chain reaction. Modern biology and biochemistry make intensive use of these techniques in recombinant DNA technology. Recombinant DNA is a man-made DNA sequence that has been assembled from other DNA sequences. They can be transformed into organisms in the form of plasmids or in the appropriate format by using a viral vector. The genetically modified organisms produced can be used to produce products such as recombinant proteins used in medical research or be grown in agricultu...

Read more »

Forensics of DNA

Forensic scientists can use DNA in blood, semen, skin, saliva or hair found at a crime scene to identify a matching DNA of an individual, such as a perpetrator. This process is called genetic fingerprinting, or more accurately, DNA profiling. In DNA profiling, the lengths of variable sections of repetitive DNA, such as short tandem repeats and minisatellites are compared between people. This method is usually an extremely reliable technique for identifying a matching DNA. However identification can be complicated if the scene is contaminated with DNA from several people. DNA profiling was developed in 1984 by British geneticist Sir Alec Jeffreys and first used in forensic science to convict Colin Pitchfork in the 1988 Enderby murders case. People convicted of certain types of crimes...

Read more »

Bioinformatics of DNA

Bioinformatics involves the manipulation, searching, and data mining of DNA sequence data. The development of techniques to store and search DNA sequences have led to widely applied advances in computer science, especially string searching algorithms, machine learning and database theory. String searching or matching algorithms, which find an occurrence of a sequence of letters inside a larger sequence of letters were developed to search for specific sequences of nucleotides. In other applications such as text editors, even simple algorithms for this problem usually suffice, but DNA sequences cause these algorithms to exhibit near worst case behaviour due to their small number of distinct characters. The related problem of sequence alignment aims to identify homologous sequences...

Read more »

Nanotechnology of DNA

DNA nanotechnology uses the unique molecular recognition properties of DNA and other nucleic acids to create self-assembling branched DNA complexes with useful properties. DNA is thus used as a structural material rather than as a carrier of biological information. This has led to the creation of two dimensional periodic lattices (both tile-based as well as using the DNA origami method) as well as three dimensional structures in the shapes of polyhedra. Nanomechanical devices and algorithmic self-assembly have also been demonstrated, and these DNA structures have been used to template the arrangement of other molecules such as gold nanoparticles and streptavidin protei...

Read more »

Research Histry of DNA

DNA was first isolated by the Swiss physician Friedrich Miescher who in 1869, discovered a microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of cells, he called it "nuclein". In 1919, Phoebus Levene identified the base sugar and phosphate nucleotide unit. Levene suggested that DNA consisted of a string of nucleotide units linked together through the phosphate groups. However, Levene thought the chain was short and the bases repeated in a fixed order. In 1937 William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure. In 1928, Frederick Griffith discovered that traits of the "smooth" form of the Pneumococcus could be transferred to the "rough" form of the same bacteria by mixing...

Read more »