In addition to the one-of-a-kind pattern engraved on our fingers, each of us possesses a unique identifier that is built within our bodies. DNA (deoxyribonucleic acid) is the genetic blueprint that determines our biological characteristics. DNA is a long molecule located in almost every cell in the human body. When we are conceived, we inherit half of our DNA from our mother and half from our father. Although every human’s DNA is 99.9% identical, the remaining 0.1% is enough to uniquely identify an individual. Our DNA is made up of about 3 billion base pairs, the building blocks of DNA composed mainly of carbon and sugar. The 0.1% (3 million) base pairs that make us unique are what constitute our DNA fingerprint.

Over the past 20 years, courts have been able to rely upon the consistent accuracy of DNA profiling, also known as DNA fingerprinting, to solve crimes. DNA profiling has even been used to solve crimes that are more than 30 years old.

Here’s how DNA profiling is done: