The distinctive patterns of human fingerprints have been recorded and categorized since the 17th century. Yet it was not until the late 19th century that the nature of the human fingerprint, as a unique and unchanging personal identifier, was recognized for its forensic value. For the last century, extremely detailed and systematic analysis of fingerprints has allowed the identification of criminal suspects.

This diagram highlights fifty independent characteristics of a single fingerprint that may be used in its identification.1

But criminal investigation is hampered by incomplete or smudged fingerprints. In 1986, when genetic profiling was first used to solve a criminal case, experts in law enforcement and justice saw the potential of this new technique: resilient molecules of DNA could be detected in trace amounts of human cells. Since each cell contains a complete copy of an individual’s unique genome, DNA profiling offered the possibility of a more versatile, but equally reliable, type of “fingerprint.”