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Dna Term Project

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DNA Testing

DNA testing is a method of identification that compares fragments of Deoxyribonucleic Acid (DNA). DNA is the genetic material found within the cell nuclei of all living things. The complete DNA of each individual is unique except in identical twins. DNA was first used in 1985 as an identification technique. It was first used to detect the presence of genetic diseases. Soon after, it was used in criminal investigations. The first criminal convictions based on DNA evidence in the U.S. occurred in 1988.

The reliability of DNA testing has increased over the years due to better techniques. It is still not one hundred percent accurate, however. There are a few factors that can contribute to inaccuracies. Reliability can be questionable if DNA segments rather than complete DNA strands are fingerprinted. Human error in interpreting tests could lead to false results. There is also the possibility of criminals planting fake DNA samples at crime scenes.

One type of DNA testing is Restriction Fragment Length Polymorphism, or RFLP. This process analyzes the variable lengths of DNA fragments with a special kind of enzyme. The process cuts DNA at a specific sequence pattern. It shows the presence or absence of DNA sample. Hybridized with DNA bind DNA sequence sample. This process was originally used for forensic investigations, however it is not used as much now because it requires large amounts of DNA. Another type of DNA testing is PCR, or Polymerase Chain Reaction. This process makes exact copies of DNA from biological samples. Only very small quantities of DNA (few skin cells) are needed. Contamination can happen, so scientists must be very careful during this process. The third type of testing is Short Tandem Repeat, or STR. Here you evaluate specific regions within nuclear DNA. Variability STR is used to distinguish one DNA from another. The FBI uses DNA profiles gathered through this process to operate local, state, and national databases The last type of DNA testing is AFLP, or Amplified



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