How do scientists know that all DNA is unique?
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No, we make presumptions given known mutation rates.  For mammals it's about 1 error in 10^9 bp.  So each time a cell replicates on average there will be 3 errors.  Also population geneticists, who study variation of DNA in populations, have established a set of makers in several mammallian species including humans and mice that look at variation at specific loci which tend to be heterozygous.  These loci are called microsattellite, or minisatellites.  There are other things population geneticists use but mostly they look at specific DNA loci via PCR and gel separation techniques.  Hope this helps
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try this \n\nhttp://en.wikipedia.org/wiki/DNA_fingerprinting
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They get DNA from nucleated cells like white blood cells (in blood and saliva) and epithelial cells (in saliva). They lyze the cells to free the DNA, centrifuge and take the fraction with the DNA, treat and amplify or multiply the DNA fragments, put markers or specific labels, determine the presence and amount of this marked or labeled fragments, and compare the distribution with known samples or DNA database. DNA results are usually one page long.
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dna is a chemical code inside every living cell that determines how the cell functions.
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DNA contains in the code itself a remarkable system of redundancy and mutability that allow it to evolve rapidly while protecting against lethal combinations.  This system seems to have been in DNA since the earliest organisms, and has been passed from organism to organism relatively unchanged for 2 billion years.\n\nRead the full article below for all the particulars.
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UPDATE: I've just read your comment so I'm leaving the difficult stuff below. \nFirst things first:\nProbably you know (but it's worth repeating) that the genetic information in each cell is kept as DNA. This DNA is able to copy parts of itself as RNA. RNA in turn builds proteins. Our bodies are not made only of proteins, but proteins are the ultimate regulators of what our body looks like and how it works. So, if a gene in your DNA synthesizes a specific RNA, and this in turn can make a particular protein, this protein will have to do with the way you look and function. Another person with a somewhat different "variety" of the same gene, will have a different appearance and/or function. Each gene codes for one protein, so it takes a really large amount of genes to code for all of them (and this is VERY simplified, the interactions are much more complex).\n\nNow for the second part: the fact that you have several really long DNA strands in each cell (these DNA strands are what can be visualized as chromosomes under special circumstances) does not mean that every single little gene in your DNA will generate RNA and ultimately produce a protein. Only a part of the DNA is actually active (and it's a small proportion), the rest is just "there" and doesn't code. And the expression of the gene (=when the gene's information becomes visible) depends on the interaction with other genes, with other substances that are cellular regulators, and many environmental factors. \n\nExample: you know Siamese cats? they have a genetic constitution such that the dark color proteins are formed especially at the body parts that are colder. So usually you get a sand-colored cat with black legs, tail, and ears. But for this pattern to show, there has to be interaction with the right temperatures. If the cat is not exposed to these colder temperatures, the dark parts don't develop. Or maybe other proteins or regulators "got in the way" of the process. And you get a cat with no dark parts (or the opposite, a very dark animal from excess cold). \nAnother example: suppose a baby is born from tall parents; they in turn had tall parents, so it's highly probable that the baby has the "tall" potential. But if this baby is not well nourished during his/her development, he/she will not reach the height that he "potentially should" have had. \nCan you see the difference? The genotype is ALL the genetic information that you have, and the phenotype is the result of the combination of this genetic information with other factors: the person/animal/plant as it is realized. \nI hope this helps you, I'll be around :-)\n\nCheck this site, it's great:\nhttp://evolution.berkeley.edu/evosite/evo101/IIIA1Genotypevsphenotype.shtml\n-------------------------------\nThe genotype is the genetic information that the said individual carries in each of his/her body cells. Much of that information is never expressed (=becomes "visible" or translates into actual characteristics), and much genetic information can yield different characteristics depending on the interaction with many environmental factors (which occur both inside and outside the cell or organism in question). Thus, the final fully developed individual is the result of the genotype ("raw" genetic information) PLUS environmental/developmental factors; the characteristics of this final product, the real individual, constitute the Phenotype. \nFor instance, an individual with a perfectly "normal" genotype may develop many types of abnormalities due to problems during pregnancy, including drugs, lack of oxygen, etc. Identical twins have the same genotype (they come from a single cell) but are never completely identical; and of course they have different personalities. This is because of all the epigenetic phenomena that influence development. And it's also the reason why reductionist approaches that s
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yes!  the only difference is finger prints (isn't that odd)\n\nlet me clarify: identical twins have the same DNA
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I'm almost 100% sure that the answer is "It ensures that the DNA will be replicated for new cells"\n\nWhat the question is talking about is the way in which the bases pair together.  I'm sure you've been taught that the bases pair as follows:  A-T and C-G.  When DNA is replicated, it is "unzipped" leaving two strands of DNA that each have bases that aren't paired.  In order to make 2 new complete strands, the correct bases must be added to each of these half-complete strands.  This is where the question comes into play.  If the bases could pair in any way possible the new strands would not be identical to the original.  This is why it is critical that A only pairs with T and C only pairs with G.\n\nI hope this helps.  Questions like this really test your knowledge of the material.  It is one thing to know A-T and C-G.  It is another to know why these combinations are critical in the process of replicating DNA.
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that is not true. The following is the way scientists determine paternity\n\n1) Dna samples are taken for both father and child\n2) The Different DnA tubes are seperated and restriction enzymes cut them up ointo smaller pieces. They work in a complicated way not worth discussin at this time\n3) Scientists place the two types of DNA fragments into a spectrophotometer with gel\n4) On one side there is an anode and another has a cathode\n5) Larger and heavier pieces of DNA migrate to the anode visa versa.\n6) Finally scientists compare where the DNA is on both tests. If the DNA strands arrive in the same relative locations as the child's DNA then the father is the father (if that makes sense)\n\n\nYOUR DNA IS NOT NEEDED NAMELY THE MOTEHRS DNA IS USELESS
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Epigenetics are silent differences in DNA that can be passed on ie. methylations. So since the DNA sequence itself isn't changed it's a lot harder to tell if someone has a disease (if this change is contributing to a disease) by the methods used today of looking to see if the DNA has differenced in the sequence. This could explain how mutations get passed from generation to generation even if their actual DNA sequence looks like everybody else's. This is a fairly new area of biology being studied.
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Though you will ignore the answer, I'll try anyway.  \n\nYour question, with explanation was a classic straw man, so I'll answer your question.\n\nI do not support ID as per se, but, all they are saying is the following:\n\nStep 1:  dna exists.\nStep 2:  later, new dna exists which could not have been eluciadated from existing dna, because there is unquestionably new and unique information in this new dna, which did not exist before.\nStep 3:  how did it happen?  \nStep 4:  it either happened by some still unknown natural or biological mechanism, or it was caused, created.\nStep 5: the natural or biological mechanism seems unlikely as the cause for strictly reasonable and logical reasons.  However, if it could be discovered, it would be one of the most important discoveries ever, and would be communicated as such.  This is still one of the mysteries in biology.  \nStep 6:  new information is not created by natural and random processes.  This just does not occur in nature.  Based on experience and logic.  \nStep 7:  based on the above, it seems that design is involved.\n\nThis is not hard logic.  The point is that you have closed your mind to the issues the ID people are trying to consider, and ID people are fully engaged in science.  What happens if you are wrong?\n\nBasically, ID does not say design is perfect, however, it could very well be optimal, and that takes intelligence, and then it is not a flaw.  ID people have answered your question many times.  Many you need to do some reading.  I cannot say the retina is shoddely wired.  Your remark was a rhetorical and opinionated remark.\n\nNot trying to give you a hard time.  Just the facts.\n\nEdit:  Anything that is proven by science, I agree with.  Duplication is well known.  I hope I was clear.  The issue is:  Here is dna without a certain new function, like a lung, or kidney, or brain, or eye, or skin, of bone, or hair, of tear duct, or immune response, etc.  Later, a 100 lines, or millions of lines of new dna exist with this code.  Duplication is not the mechanism, for the function did not exist, and requires some pretty profound new engineering to create.  The unanswered question is:  how did it happen?  Randomness cannot be part of the solution, since the improbabilities are far too great.  \n\nCan this question be answered, or is it still open?  The answer I usually get is, well just because we do not know, does not mean we should accept the possibility of a creator.  I say, you should consider both, until we have an answer.  You may lean one way or the other, but both are still possibilities.  \n\nThe most knowledgeable scientists agree for example, in cosmology, the closer we get to the beginning of the universe, the more the questions become philosophical and theological.  You are discounting a vital side of the story.
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Yes, it has DNA. A fair amount of DNA sequenciing has been done on DNA from a frozen mammoth. Researchers have also been able to assemble the complete sequence of the mitochondria.
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Here is how science proves the existence of a Creator.\n\nYou are here: Science >> DNA Double Helix \n\nDNA Double Helix: A Recent Discovery of Enormous Complexity\nThe DNA Double Helix is one of the greatest scientific discoveries of all time. First described by James Watson and Francis Crick in 1953, DNA is the famous molecule of genetics that establishes each organism's physical characteristics. It wasn't until mid-2001, that the Human Genome Project and Celera Genomics jointly presented the true nature and complexity of the digital code inherent in DNA. We now understand that each human DNA molecule is comprised of chemical bases arranged in approximately 3 billion precise sequences. Even the DNA molecule for the single-celled bacterium, E. coli, contains enough information to fill all the books in any of the world's largest libraries. \n\nDNA Double Helix: The "Basics"\nDNA (deoxyribonucleic acid) is a double-stranded molecule that is twisted into a helix like a spiral staircase. Each strand is comprised of a sugar-phosphate backbone and numerous base chemicals attached in pairs. The four bases that make up the stairs in the spiraling staircase are adenine (A), thymine (T), cytosine (C) and guanine (G). These stairs act as the "letters" in the genetic alphabet, combining into complex sequences to form the words, sentences and paragraphs that act as instructions to guide the formation and functioning of the host cell. Maybe even more appropriately, the A, T, C and G in the genetic code of the DNA molecule can be compared to the "0" and "1" in the binary code of computer software. Like software to a computer, the DNA code is a genetic language that communicates information to the organic cell. \n\nThe DNA code, like a floppy disk of binary code, is quite simple in its basic paired structure. However, it's the sequencing and functioning of that code that's enormously complex. Through recent technologies like x-ray crystallography, we now know that the cell is not a "blob of protoplasm", but rather a microscopic marvel that is more complex than the space shuttle. The cell is very complicated, using vast numbers of phenomenally precise DNA instructions to control its every function. \n\nAlthough DNA code is remarkably complex, it's the information translation system connected to that code that really baffles science. Like any language, letters and words mean nothing outside the language convention used to give those letters and words meaning. This is modern information theory at its core. A simple binary example of information theory is the "Midnight Ride of Paul Revere." In that famous story, Mr. Revere asks a friend to put one light in the window of the North Church if the British came by land, and two lights if they came by sea. Without a shared language convention between Paul Revere and his friend, that simple communication effort would mean nothing. Well, take that simple example and multiply by a factor containing many zeros. \n\nWe now know that the DNA molecule is an intricate message system. To claim that DNA arose by random material forces is to say that information can arise by random material forces. Many scientists argue that the chemical building blocks of the DNA molecule can be explained by natural evolutionary processes. However, they must realize that the material base of a message is completely independent of the information transmitted. Thus, the chemical building blocks have nothing to do with the origin of the complex message. As a simple illustration, the information content of the clause "nature was designed" has nothing to do with the writing material used, whether ink, paint, chalk or crayon. In fact, the clause can be written in binary code, Morse code or smoke signals, but the message remains the same, independent of the medium. There is obviously no relationship between the information and the mater
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Because you want to test a portion which is unique.  The vast majority of our DNA is exactly like everyone else's- In the normal gene sequence, you might literally have a stretch of 10,000 base pairs without a single difference.  It's like that because it's critical that there not be mutationsm.  The variable regions do not code for proteins, and thus it's not critical that the cell maintain this sequence- It can vary without hurting the cell (or the person).  Because of that, there are a great many mutations in these area, making them unique, and therefore useful for identification.
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All great answers.\nIt is nearly impossible to determine race.  \n\nAnalyzing DNA in a petri dish you would be able to determine probably eye color, probably hair color, and some other identifying informaton. But not race. You could link to some degree of certainty the sample to a known population, but not with enough specifity to hold up in court.\n\nIn general, we as a species are all very similar. Distinct culture and populations have some unique traits that repeat due to the closed nature of that society but as a species we work out genetically to be quite the same. \n\nThink of it this way. If an alien came to Earth, took random samples of people from all over, they would conclude we are all the same. That any variations in structure or color must be normal variety in the genome.
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The DNA Double Helix is one of the greatest scientific discoveries of all time. First described by James Watson and Francis Crick in 1953, DNA is the famous molecule of genetics that establishes each organism's physical characteristics. It wasn't until mid-2001, that the Human Genome Project and Celera Genomics jointly presented the true nature and complexity of the digital code inherent in DNA. We now understand that there are approximately 35,000 genes in each human DNA molecule, comprised of chemical bases arranged in approximately 3 billion precise sequences. Even the DNA molecule for the single-celled bacterium, E. coli, contains enough information to fill all the books in any of the world's largest libraries.
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Since you made your question sound real with intent on getting an answer even if you don't except it I will try to explain.\nArthur Conan Doyle for his character Sherlock Holmes wrote and I quote loosely.. "You solve a mystery by removing posiblities. What ever is left no matter how improbable is the truth.."\nThat leads me to chirality. Although two chemical molecules may appear to have the same elements and similar properties, they can still have different structures. When two molecules appear \nidentical and their structures differ only by being mirror images of each other, those molecules are said to have chirality. Your left and right hands illustrate chirality. When a random chemical reaction is used to prepare molecules having chirality, there is an equal opportunity to prepare the left-handed isomer as well as the right-handed isomer. It is a scientifically verifiable fact that a random chance process, which forms a chiral product, can only be a 50/50 mixture of the two optical isomers. There are no exceptions. Chirality is a property that only a few scientists would even recognize as a problem. The fact that chirality was missing \nin those amino acids is not just a problem to be debated, it points to a catastrophic failure that "life" cannot come from chemicals by natural processes. If proteins and DNA were formed by chance, each and every one of the components would be a 50/50 mixture of the two optical isomers. This is not what we see in natural proteins or in natural DNA. How can a random chance natural process create proteins with thousands of "L" molecules, and then also create DNA with billions of "R" molecules? Does this sound like random chance or a product of design? Chirality is not just a major problem for evolution; it is a dilemma. It is this handedness that gives DNA the spiral shaped helical structure. If one molecule in the DNA structure had the wrong chirality, DNA would not exist in the double helix form, and DNA would not \nfunction properly. The entire replication process would be derailed like a train on bad railroad tracks. In order for DNA evolution to work, billions of molecules within our body would have to be generated with the "R" configuration all at the \nsame time, without error. If it is impossible for one nucleotide to be formed with chirality, how much less likely would it be for billions of nucleotides to come together exactly at the same time, and all of them be formed with the same chirality? According to evolution, natural processes must explain everything over long periods of time. However, the process that forms chirality cannot be explained by natural science in any amount of time.\nThis is evidence straight from the labs of Science. The Bible has nothing to do with these facts. Yet the magnitude of the problem indicates that there WAS a creative force behind all life and that the spontaneous life generation that most scientist hold up as fact is at best far fetched and worst impossible.....   Jim