i would like to know more about the type of nutaion ecrase by the U.V on the DNA .?
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Mutation not nutation\nIn biology, mutations are changes to the genetic material (usually DNA or RNA). Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses, or can occur deliberately under cellular control during the processes such as meiosis or hypermutation. In multicellular organisms, mutations can be subdivided into germline mutations, which can be passed on to progeny and somatic mutations, which cannot be transmitted to progeny. Mutations, when accidental, often lead to the malfunction or death of a cell and can cause cancer. Mutations are considered the driving force of evolution, where less favorable (or deleterious) mutations are removed from the gene pool by natural selection, while more favorable (beneficial or advantageous) ones tend to accumulate. Neutral mutations are defined as mutations whose effects do not influence the fitness of either the species or the individuals who make up the species. These can accumulate over time. Contrary to tales of science fiction, the overwhelming majority of mutations have no significant effect, since DNA repair is able to revert most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells.\n\nBy effect on structure\nThe DNA sequence of a gene can be altered in a number of ways. Gene mutations have varying effects on health, depending on where they occur and whether they alter the function of essential proteins. Structurally, mutations can be classified as:\n\nSmall-scale mutations affecting one or a few nucleotides, including: \nPoint mutations, often caused by chemicals or malfunction of DNA replication, exchange a single nucleotide for another. Most common is the transition that exchanges a purine for a purine (A ↔ G) or a pyrimidine for a pyrimidine, (C ↔ T). A transition can be caused by nitrous acid, base mispairing, or mutagenic base analogs such as 5-bromo-2-deoxyuridine (BrdU). Less common is a transversion, which exchanges a purine for a pyrimidine or a pyrimidine for a purine (C/T ↔ A/G). A point mutation can be reversed by another point mutation, in which the nucleotide is changed back to its original state (true reversion) or by second-site reversion (a complementary mutation elsewhere that results in regained gene functionality). These changes are classified as transitions or transversions. An example of a transversion is adenine being converted into a cytosine. There are also many other examples that can be found. Point mutations that occur within the protein coding region of a gene may be classified into three kinds, depending upon what the erroneous codon codes for: \nsilent mutations: codes for the same amino acid \nmissense mutations: codes for a different amino acid \nnonsense mutations: codes for a stop, which can truncate the protein \nInsertions add one or more extra nucleotides into the DNA. They are usually caused by transposable elements, or errors during replication of repeating elements (e.g. AT repeats). Insertions in the coding region a gene may alter splicing of the mRNA, or cause a shift in the reading frame (frameshift), both of which can significantly alter the gene product. Insertions can be reverted by excision of the transposable element. \nDeletions remove one or more nucleotides from the DNA. Like insertions, these mutations can alter the reading frame of the gene. They are irreversible. \nLarge-scale mutations in chromosomal structure, including: \nAmplifications (or gene duplications) leading to multiple copies of chromosomal regions, increasing the dosage of the genes located within them. \nDeletions of large chromosomal regions, leading to loss of the genes within those regions. \nMutations whose effect is to juxtapose previously separate pieces of DNA, potentially bringing together separate genes to form functionally distinct fusion genes (e.g. bcr-abl). These
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There are multiple start codons, depending on the species.  But I'm pretty sure that there are always a few oddities in how different species might encode information is slightly non-standard ways.
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Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. DNA is a long polymer of nucleotides (a polynucleotide) and encodes the sequence of the amino acid residues in proteins using the genetic code, a triplet code of nucleotides.\n\nIn complex eukaryotic cells such as those from plants, animals, fungi and protists, most of the DNA is located in the cell nucleus. By contrast, in simpler cells called prokaryotes, including the eubacteria and archaea, DNA is not separated from the cytoplasm by a nuclear envelope. The cellular organelles known as chloroplasts and mitochondria also carry DNA.\n\nDNA is often referred to as the molecule of heredity as it is responsible for the genetic propagation of most inherited traits. In humans, these traits can range from hair colour to disease susceptibility. During cell division, DNA is replicated and can be transmitted to offspring during reproduction. Lineage studies can be done based on the facts that the mitochondrial DNA only comes from the mother, and the male Y chromosome only comes from the father.\n\nEvery person's DNA, their genome, is inherited from both parents. The mother's mitochondrial DNA together with twenty-three chromosomes from each parent combine to form the genome of a zygote, the fertilized egg. As a result, with certain exceptions such as red blood cells, most human cells contain 23 pairs of chromosomes, together with mitochondrial DNA inherited from the mother.\n\nContrary to a common misconception, the DNA is not a single molecule, but rather a pair of molecules joined by hydrogen bonds: it is organized as two complementary strands, head-to-toe, with the hydrogen bonds between them.[1] Each strand of DNA is a chain of chemical "building blocks", called nucleotides, of which there are four types: adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T).[1] (Thymine should not be confused with thiamine, which is vitamin B1.) In some organisms, most notably the PBS1 phage, Uracil (U) replaces T in the organism's DNA.[2] These allowable base components of nucleic acids can be polymerized in any order giving the molecules a high degree of uniqueness.\n\nBetween the two strands, each base can only "pair up" with one single predetermined other base: A+T, T+A, C+G and G+C are the only possible combinations; that is, an "A" on one strand of double-stranded DNA will "mate" properly only with a "T" on the other, complementary strand; therefore, naming the bases on the conventionally chosen side of the strand is enough to describe the entire double-strand sequence.[1] Two nucleotides paired together are called a base pair. On rare occasions, wrong pairing can happen, when thymine goes into its enol form or cytosine goes into its imino form. The double-stranded structure of DNA provides a simple mechanism for DNA replication: the DNA double strand is first "unzipped" down the middle, and the "other half" of each new single strand is recreated by exposing each half to a mixture of the four bases. An enzyme makes a new strand by finding the correct base in the mixture and pairing it with the original strand. In this way, the base on the old strand dictates which base will be on the new strand, and the cell ends up with an extra copy of its DNA.\n\nDNA contains the genetic information that is inherited by the offspring of an organism; this information is determined by the sequence of base pairs along its length. A strand of DNA contains genes, areas that regulate genes, and areas that either have no function, or a function yet unknown. Genes can be loosely viewed as the organism's "cookbook" or "blueprint".\n\n\n\nCloning is the process of creating an identical copy of an original. A clone in the biological sen
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DNA is a polymer. The monomer units of DNA are nucleotides, and the polymer is known as a "polynucleotide." Each nucleotide consists of a 5-carbon sugar (deoxyribose), a nitrogen containing base attached to the sugar, and a phosphate group. There are four different types of nucleotides found in DNA, differing only in the nitrogenous base. The four nucleotides are given one letter abbreviations as shorthand for the four bases. \n\nA is for adenine \nG is for guanine \nC is for cytosine \nT is for thymine \nThe DNA backbone is a polymer with an alternating sugar-phosphate sequence. The deoxyribose sugars are joined at both the 3'-hydroxyl and 5'-hydroxyl groups to phosphate groups in ester links, also known as "phosphodiester" bonds
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well, hope these help:\n\nhttp://www.bbc.co.uk/dna/h2g2/A388217\n\nhttp://www.chemistrysurvival.com/
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Just have a look at the sites\nhttp://www.DNA-NEWS.ORG \nhttp://www.GENETIC.ORG.UK \nhttp://www.cell-stem.com\nhttp://www.dna-research.org\nhttp://www.dna-rna.org\nhttp://www.dnasequencing.info\nhttp://www.junk-dna.com\nhttp://www.testing-dna.org
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A, B, and Z DNA are the 3 main types which refer to the orientation of the structure of the double-helix, and therefore, the ability of the DNA to express (turn on) genes.\n\nOther designations are gDNA (genomic DNA), also called wtDNA (wild-type DNA) which is DNA as it is found normally in nature.  cDNA is DNA which contains only the exon portions of genes and omite the intron portions.  Introns are the portions of genes which are spliced out once the gene is actually expressed.  The role of introns in genes is not functional and is speculated structural.\n\nIn molecular biology, we use many such working designations to determine the type of DNA we are using.  These help us to define the structure and nature of the form of a gene we are using for research purposes.
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its DNA it is a part of a gene which is a thing wich codes for something. it is a double stranded structure. its also called a polynucleotide.
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Nearly Complete Genomic Libraries of Higher Organisms Can Be Prepared by λ Cloning\n\nWith the availability of λ phage cloning vectors, preparation of genomic libraries for higher organisms, including humans, is feasible. A genomic library is a set of λ (or plasmid) clones that collectively contain every DNA sequence in the genome of a particular organism. Figure 7-12 summarizes the general procedure for constructing a λ genomic library. The λ DNA first is treated with a restriction enzyme to produce fragments called λ vector arms, which have sticky ends and together contain all the genes necessary for lytic growth. This step frees the nonessential region in the middle of the λ genome; this region is separated from the λ arms and discarded. Genomic DNA then is extracted from a cell type that contains all the genetic information of the organism under study. Sperm cells or cells of an early embryo often are used as sources of mammalian DNA. The extracted DNA then is cleaved by a restriction enzyme to produce ≈20-kb fragments with sticky ends complementary to the sticky ends on the λ vector arms being used.\n\nThe λ arms and the collection of genomic DNA fragments are mixed in about equal amounts. The complementary sticky ends on the fragments and λ arms hybridize and then are joined covalently by DNA ligase. Each of the resulting recombinant DNA molecules contains a foreign DNA fragment located between the two arms of the λ vector DNA. The ligated recombinant DNAs then are packaged into λ virions in vitro as described above. Only DNA molecules of the correct size can be packaged to produce fully infectious recombinant λ virions.\n\nFinally, the recombinant λ virions are plated on a lawn of E. coli cells to generate a large number of recombinant λ plaques. Since each plaque arises from a single recombinant virion, all the progeny λ phages that develop are genetically identical and constitute a clone carrying a particular genomic DNA insert. The different plaques correspond to distinct phage clones, each carrying a different DNA insert, and collectively they constitute a λ genomic library. Multiple λ vectors have been constructed containing different restriction sites, so that restriction fragments generated by a variety of restriction enzymes can be cloned in λ vectors.\n\nIn constructing a library of genomic DNA, the DNA commonly is cleaved with a restriction enzyme that recognizes a 4-bp restriction site (e.g., Sau3A, as shown in Figure 7-12). A specific 4-bp sequence will occur on average once every 44 = 256 base pairs. Complete digestion of the human haploid genome, which contains ≈3 × 109 base pairs, would yield somewhat more than 107 nonoverlapping different fragments. However, to increase the probability that all regions of the genome are successfully cloned and represented in the λ genomic library, the genomic DNA usually is only partially digested to yield overlapping restriction fragments of ≈20 kb (Figure 7-13). In a large λ library constructed from such overlapping restriction fragments, a specific sequence of genomic DNA (e.g., the gene encoding β-globin) often is contained in or extends over several “overlapping” clones. By a technique called chromosome walking, described in the next chapter, overlapping genomic clones can be ordered.\n\nThe size of a genomic library for a given organism depends on the amount of DNA in that organism's haploid genome. If the human genome of about 3 × 109 base pairs is cleaved into 20-kb fragments for insertion into a λ vector, then roughly 1.5 × 105 different recombinant λ phage virions would be required to constitute a complete library. Because the restriction fragments of human DNA are incorporated into phages randomly, about 106 recombinant phages are necessary to assure that each region of human DNA has a 90 – 95 percent chance of being included.\n\nEach plaque produced by a recombinant bacteriophage λ contains large numbers of recombi
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One word contradicts your "facts". \n\nPlasmids.\n\nPlasmids are non-chromosomal loops of DNA found in bacteria.  They often contain antibacterial resistance genes, or give the ability to use different sugars.  These plasmids are commonly shared by bacteria.  This is a gain of genetic information.\n\nNow, it is true that we only have 4 types of nucleotides in DNA, and they make about 20 amino acids.  This is conserved in all life forms. But from this, a countless number of proteins can be made, and have a nearly infinite number of effects.  Your suggesting could be likened to saying that we can never invent a new word, since we only have 26 letters.  \n\nPlease provide a source for your claims, perhaps then we can understand how you arrived at such a conclusion.
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deoxyribonucleic acid-but you dont really need to know that
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GGATCGA\n\nGuanine pairs with adonine and cytosine pairs with thymine.
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DNA is composed of 4 bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Uracil (U), is rarely found in DNA except as a result of chemical degradation of Cytosine, but the DNA of some viruses (notably PBS1 phage DNA) and RNA (Ribonucleic Acid), has Uracil instead of Thymine.\n\nEach base on one strand forms a bond with just one kind of base on another strand, called a "complementary" base: A bonds with T, and C bonds with G. Therefore, the whole double-strand sequence can be described by the sequence on one of the strands, chosen by convention. Two nucleotides paired together are called a base pair.\n\nIn a DNA double helix, two polynucleotide strands can associate through the hydrophobic effect and pi stacking. Which strands associate depends on complementary pairing. Each base forms hydrogen bonds readily to only one other base, A to T forming two hydrogen bonds, and C to G forming three hydrogen bonds. The GC content and length of each DNA molcule dictates the strength of the association; the more complementary bases exist, the stronger and longer-lasting the association, characterised by the temperature required to break the hydrogen bond, its melting temperature (also called Tm value))-.
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click here:http://rds.yahoo.com/_ylt=A0geuuCMJFdFWDsB6.FXNyoA;_ylu=X3oDMTE2NXZmaDBwBGNvbG8DZQRsA1dTMQRwb3MDOQRzZWMDc3IEdnRpZANERlg1XzMw/SIG=122s68rjs/EXP=1163425292/**http%3a//www.wellcome.ac.uk/en/fourplus/DNA.html
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dna and genetic coding of chromosomes.
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you can read up on it here\n\nhttp://en.wikipedia.org/wiki/DNA\n\nbut even better would be to buy related books and take related courses
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Go to answers.com and type molecular mutagensis at search you get links go through them.