DNA is the molecule that makes up our genetic code. It is a long biological strand of atoms that tells our cells what kind of living organism we are- in this case, anyone reading this is likely human. Our DNA is also unique to us- because it has so many genes and phenotypes, there is no way two people have the same exact DNA. The only possible exception is identical twins, but this is not strictly true, as mutations after each twin's birth will take effect, as they get older. DNA has many medical and scientific applications, but it is also used in crime scenes and criminology.
What DNA is
DNA is a double helix strand molecule that sits in the nucleolus of our cells. Discovered in the fifties, in recent years scientists have also managed to map where most of the genes on the human DNA complex are, and what they code for. This was called the Human Genome Project. DNA is very important, because other parts of the cell copy it and use it to produce different proteins that have different functions in our body. We do not fully understand how DNA works, but we are able to transplant DNA from one species to another, identify individuals from their genome, and there is a host of other applications for this technology.
Crimes DNA can be used for
There are different crimes that DNA can be used for. The most common type of crime is violence. This does include sexual violence, by both genders- sexual fluids from both genders have DNA in them, so they can be used to prove who had sex with whom in many cases. This is useful for other sexual investigations, such as charges of infidelity. Our DNA is in our blonde, bone, and other tissues as well- it is very difficult not to leave even a hair at a crime scene, so if a violent crime is committed it is often possible to look at the DNA and see who was at the scene for some length of time.
Using DNA as evidence
DNA has a lot of applications, and it is a matter of finding what to use and what makes sense for an individual case. If blood, hair, or even nail clippings are found, it can be shown that it belongs to a specific person, and this often can put a person at a specific time and place. For cases such as infidelity, it is possible to use DNA evidence to determine paternity. There are a lot of forensic applications of DNA technology, and a lot of wrongly convicted men have been released due to DNA evidence. A lot of murders and other crimes have also been proven with DNA evidence.