DNA testing is now a common part or our everyday lives; the uses of it span from forensic tests on crime scenes to paternity tests to gene therapy.
In humans, 99.9% of our DNA has the same sequencing as every other human on the planet. This means that, when carrying out DNA testing, scientists are looking for the difference in 0.1% of our genetic makeup. These differences are called genetic markers, and these are what make us unique.
However, the more closely related you are to another person, the more similar your genetic markers will be, with identical twins having identical markers. When carrying out a parental identity test, scientists will look at the similarities between the two samples to determine the result. Due to the fact that all cells in the body contain exactly the same DNA, samples can be removed from anywhere and still prove effective and accurate.
The first example of DNA being used to convict someone in the USA was serial killer Timothy Wilson Spencer, who was sentenced to death using DNA evidence. In the same trial, the man previously accused of the crime, David Vasquez, was simultaneously cleared and pardoned.
Science has advanced so much in the last centuary that the possibilities for technologies such as these are endless.