DNA Forensics

Gabby Lacobie and Kaylee Smith

DNA Fingerprinting

DNA (deoxyribonucleic acid) fingerprinting - A test to identify and evaluate the genetic information called DNA in a person's cells. DNA fingerprinting, also called DNA typing, DNA profiling, genetic fingerprinting, genotyping, or identity testing.


Fun Fact-DNA Fingerprinting has saved 329 wrongfully convicted people, including 18 who spent time on death row.

Who invented DNA Forensics?

This technique was developed by geneticist Alec Jeffreys in 1984, after he noticed the certain sequence of minisatellites (repetitive DNA) were repeated in genes, but did not contribute to the functions of them. Jegffreys discovered that every person has a unique pattern of minisatellites, the only exception being identical siblings.

How is DNA used to identify people?

To identify a person using DNA, forensic investigators first have to create a genetic profile of the DNA. A genetic profile is a set of numbers that specifically to the person. To do this they must break down the DNA and look for repeating genes. Since humans share 99% of their DNA, the investigators are looking for Short Tandem Repeats, also known as STR, which vary in between individuals. Because a person inherits different genes from each parent, the likely hood of two unrelated people having the same pattern is highly improbable.

Taking the Genetic Profile one step further

The national DNA database is a government database containing genetic profiles of previously convicted criminals, people facing federal charges, political offences, and non-US citizens detained in the United States. The database is also called CODIS or Combined DNA Index System. Your DNA can be taken without a warrant or conviction as long as there is probable cause, afterwards it can be put in the system.