Forensic DNA Analysis
Forensic DNA analysis is a relatively new field of forensic science. It was introduced only after British geneticists Sir Alec Jeffreys (born 1950)developed techniques for DNA fingerprinting in 1985.
The Process of Forensic DNA Analysis
The process of forensic DNA analysis begins with obtaining samples containing DNA such as bodily fluids (blood, saliva, semen), tissue samples, bones or hair that are found on the scene of crime, victim or personal items. After the DNA is contracted, most often by using short tandem repeat analysis, an identification of the suspect is searched for in DNA databases.
Forensic DNA analysis relies greatly on DNA databases. These are collections of genetic codes which allow forensic scientists to identify a person, of course if he/she is already in the database. The largest DNA database is the Combined DNA Index System which is managed by the United States government. In 2007, it held more than 5 million genetic codes. The UK has its own DNA database, known as the National DNA Database (NDNAD) which contains almost as much DNA profiles as that in the United States despite the fact that the UK has smaller population. The NDNAD was founded in 1995 and in March 2012, it contained nearly 6 millions profiles.
Notable Cases Involving the Use of Forensic DNA Analysis
In 1986, Richard Buckland was exonerated of rape and murder of a teenage girl in Leicestershire on the basis of DNA profiling despite the fact that he admitted the crime. This was the first time DNA profiling was used in criminal investigation.
In 1987, Colin Pitchfork became the first person to be caught and convicted on the basis of forensic DNA analysis. Pitchfork was found to be responsible for rape and murder of two girls in Leicestershire.
In 1987, Florida rapist Tommy Lee Andrews became the first person in the United States to be convicted on the basis of DNA evidence.
In 1988, Gary Dotson became the first person whose conviction was overturned on the basis of DNA profiling. He was falsely accused and found guilty of rape in 1979.
In 1992, DNA evidence proved that Josef Mengele, the Nazi SS physician in the concentration camp Auschwitz was buried in Brazil as Wolfgang Gerhard.
In 1994, the Canadian forensic scientists solved a murder case on the basis of DNA testing of hairs from a cat called Snowball. This was the first use of non-human DNA to solve a crime.
In 2009, Sean Hodgson was released on the basis of DNA evidence after spending 27 years in jail for murder of Teresa De Simon in Southampton. The case has been reopened after analysis of DNA from the scene proved that it isn’t Hodgson’s.