Only 10% of nuclear DNA codifies what we are and what we are like. Of that 10%, human beings share nearly everything. So, if what we want is something that will serve to tell certain people apart from others, the codifying DNA, in general terms and although it has its polymorphisms, will serve little purpose.
On the other hand, within the non-codifying DNA there are areas of extraordinary variability between one person and another, which we call “polymorphisms”. Also, as a result of the use we make of it, they are called DNA markers.
From the described biological samples, the DNA is extracted by means of the organic extraction method of formaldehyde/chloroform, then the DNA is purified and by means of a polymerase chain reaction technique a total of sixteen genetic markers validated by STADNAP (Standard of DNA profile techniques of the European Union) and we recommend by the ISFG (International Society of Forensic Genetics). And the PCR products are analysed by means of the fragment analysis technique, using an automatic DNA sequencer.