Blog # 13: DNA

DNA has changed the way police and federal agencies look for evidence, collect evidence, eliminate suspects, and how they investigate crimes overall. Not to long ago investigators could only put a criminal at the spot of the crime through eye-witness reports, and if no one saw the crime there was not much the investigators could do. But with the use of DNA testing if any partical of the criminal's body is left at the scene, and is picked up by csi units, it can be matched to the criminal. So DNA is able to put the criminal at the scene without a witness.

The two main types of DNA testing are PCR and RFLP. IN the PCR testing two pieces of the DNA strand are continously copied then at a certain point the copying is stopped. In RFLP testing restriction enzymes cut the DNA in specific sequences. When the enzymes cut the DNA the strands are at different lengths which can be prepared for electrophoresis.