In the early 1980s, geneticist Alec Jeffreys of Leicester University discovered that DNA, the nucleic acid molecule found in all living organisms, could be used to isolate a “genetic marker” unique to each individual. This marker can be found in hair, blood, saliva, and other parts of the body. Not all testing procedures evaluate every aspect of DNA, but DNA evidence can be important in the establishment of paternity, the determination of familial relations for inheritance purposes, and the identifi cation of criminal suspects....