The use of PCR in Forensic DNA Analysis

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml

I have been researching the uses of biotechnology in Forensics and have come upon some very useful information in regards to how decades old DNA can be restored. In the past, DNA that had been improperly stored or stored for too long had a good chance of degrading and becoming useless to the law enforcement community. This however, due to some recent innovation in the last few years is almost a thing of the past.

Years ago a sample of DNA the size of a quarter was required to get accurate incriminating information. Now with PCR or Polymerase Chain Reaction analysis we can take very minute amounts (a matter of a few skin cells) and even degraded samples of DNA and amplify them. This process works by heating the DNA, denaturing its proteins and then allowing it to cool in the presence of a polymerase, which replicates the DNA. This process is done repeatedly until sufficient genetic material has been produced. Since DNA is produced by a system of exact copies the new material is just like the old in every way.

This innovation has allowed the re-opening of many cold cases in which the evidence had been unable to be analysed in the past. I believe this to be a great benefit to the justice system in that previous evidence that was once considered unusable but would have saved someone jail time or put a criminal behind bars can now be recovered and properly analysed.

I do not know of any controversy as of yet with this process other than the statute of limitations laws are currently under scrutiny because of the new ability to recover once lost evidence. There are now states who are changing the statute of limitations to start upon the discovery of new DNA evidence. I think overall that this technology is more of a boon than a bane. I hope that someday, evidence once stored on a shelf thought to be too degraded for use in court may be of use due to this technology and that justice will be served.