Advances in forensic science have allowed for a greater reliance on minute quantities of DNA evidence.
Every person’s genetic make-up is unique. This can be beneficial in exonerating the innocent as well as identifying the guilty.
But there is a difference between the full genetic profile of a person and interpreting the forensic evidence in a crime scene on which a match is based.
Evidence based profiles may be incomplete, or a mixture from two or more people.
Apparently incriminating traces of DNA from bodily fluids or skin cells may have an innocent accidental source or be misidentified based on expectation, particularly in domestic settings where profiles may partially coincide and innocent transfer of genetic material from one person to another is commonplace.