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Northeastern University
Chemistry & Chemical Biology
CHEM 1107
Adam Hall

Introduction In the world of forensic science DNA typing is a very new and revolutionary way to identify and compare suspects In 1985 it was discovered that certain portions of the DNA structure are as unique as fingerprints of different individuals This now allowed forensic scientists to link biological evidence to victims and suspects with absolute certainty Biological evidence such as blood saliva semen tissue and hair could now be used as valid evidence that would be extremely difficult to disputeThe Chief of Police received a threatening letter in an ordinary letter envelope Concerned about the violent contents of the letter the department is tasked with identifying the person who sent the letter DNA was found on the seal of the envelope presumably from the saliva of a suspect when he or she sealed the letter and sent it Three people who had recently had violent encounters with the police chief were taken into the station as suspects and DNA was pulled using a buccal swab These samples must be compared to the DNA sample found in the envelope to determine the perpetrator The goal of this lab is to pull the Short Tandem Repeats STRs of the DNA and use them to compare the DNA profiles of the three suspects and the DNA from the envelopeTo ensure we have enough DNA to test the sample from the envelope with the suspects we must first perform a polymerase chain reaction to replicate the DNA and then it can be run through capillary electrophoresis to separate the DNA and use the patterns to potentially find a match for the DNAExercise 1 PCR of DNA SamplesIntroduction Often small or broken pieces of DNA are recovered at crime scenes It would be very difficult to work with such insufficient evidence but the process of Polymerase Chain Reaction PCR makes everything easier Using this procedure these DNA fragments can be copied Using a thermal cycler and DNA polymerase every cycle that the DNA runs through the amount of DNA at the beginning doubles This can produce a massive amount of DNA samples very quickly This DNA can then be used to create a profile that can be compared with that of the suspects in this case Purpose To replicate the sample DNA extract using the Polymerase Chain Reaction MaterialsDNA Extract in PCR tubeMaster MixMicropipetteDNA Thermal CyclerProcedure1Take the PCR tube containing the extracted DNA sample micropipette and the bottle of Master Mix
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