Understanding DNA testing: What is it?
If you’re writing crime, DNA will probably feature. Understanding DNA testing is vital.
One cornerstone of forensic science is DNA testing. DNA (deoxyribonucleic acid) is the genetic material present in every cell and each individual has a unique DNA Profile (even identical twins).
Forensic scientists can extract DNA for profiling from samples of human cells found at a crime scene, including blood, semen, hair and even sweat. They can then compare this profile to samples taken from suspects and/or held on Police databases from previous cases to find a match.
History
A British scientist, Sir Alec Jeffreys, developed DNA profiling in the 1980s.
1983
The case of Colin Pitchfork was the first murder conviction based on DNA profiling. After going missing, Lynda Mann, a young girl, was found murdered in the grounds of Carlton Hayes psychiatric hospital in Narborough, Leicestershire, in November 1983. Forensic examination of DNA samples at the scene showed only 10% of men had the same type. However, the police did not find a suspect.
1986
In 1986, they found another girl, Dawn Ashworth, murdered in the nearby village of Enderby. During this investigation DNA samples from this crime scene showed the same blood type. Richard Buckland, a local teenager with learning disabilities who worked at the psychiatric hospital, confessed to Dawn Ashworth’s murder. He did not admit to killing Lynda Mann.
Using the revolutionary new technique, scientists compared the DNA samples with blood from Richard Buckland. This proved that the same man murdered both girls, but that this man was not Richard Buckland. He became the first person exonerated using DNA.
1987
In 1987, in the first ever mass DNA screen, police and forensic scientists screened blood and saliva samples from 4,000 men. All aged between 17 and 34 living in the villages of Enderby, Narborough and nearby Littlethorpe and without an alibi. The turn out rate was 98%, but the screen did not find any matches. They expanded the screen to men with an alibi, but still did not find a match.
In August, a woman overheard a colleague, Ian Kelly, boasting that he’d given a sample posing as a friend, Colin Pitchfork. Pitchfork persuaded Kelly to take the test claiming he’d already given a sample for a friend with a flashing conviction. The police arrested Colin Pitchfork in September 1987, and scientists found his DNA profile matched the murderer.
1988
In January 1988, the Courts sentenced Colin Pitchfork to life imprisonment with instructions to serve a minimum of 30 years.
Present day
In June 2021, the parole board controversially decided that Pitchfork was suitable for release, leading to a public outcry.
In the last few weeks, the UK courts reviewed and upheld the parole board’s decision.
Final thoughts…
The importance of DNA profiling cannot be underestimated, and it remains a key component of tackling crime. If you are writing crime fiction, the chances are DNA will feature in your plot and it’s worth taking the time to understand the process. Forensics for Dummies by DP Lyle is a great resource for writers wanting to know more.
