For decades, the news media and Hollywood would have you believe that DNA evidence is some sort of miracle. When it first became a legally admissible type of evidence, there was a lot of buzz over it. People have been cleared of crimes and released from prison after serving decades for crimes they did not commit all because of DNA evidence. So, it sounds wonderful. It seems like it can solve any crime. However, that is not entirely true.
According to JSTOR Daily, DNA is rather complex. There is no denying that it has done amazing things, but it is not a miracle answer to finding out who committed a crime. There are several issues with this type of evidence that could lead to it convicting the wrong person.
It helps to know that all people share 99.9 percent of DNA. That .1 percent is the only part looked at by forensics when using DNA in a crime analysis. Close relatives do not even have a .1 percent difference, which brings about the first possible issue. A relative of the real criminal could go down for the crime because the DNA closely matches.
Another issue is that the DNA profile used is usually a partial profile. It may not be able to pinpoint the person it belongs to. Partial profiles often can be incorrect.
Lastly, there is the chance for DNA to come onto a crime scene as a transfer from someone else or to stick around from a person who may have been at the scene long before the crime occurred. As technology advances, the chances of this type of DNA being found at crim scenes increases, which could lead to false convictions.
It is important for juries to be told DNA is not definitive proof. It needs presented in ratios instead of as fact. For example, it should show the ratio of possible guilt to possible innocence. This will allow a jury to better understand it. This information is for education and is not legal advice.