New Zealand's DNA Databank
In 1995, New Zealand became the second country in the world to collect and store DNA profiles in a databank. Since then, forensic scientists and police have used the National DNA Databank to solve thousands of crimes.
Who runs the National DNA Databank?
What is on the DNA Databank?
The DNA Databank contains DNA profiles. A DNA profile is a series of numbers that represents the DNA types of the person. It is based on specific sections of DNA known to be extremely variable between people.
The DNA is obtained mostly from samples of cells from the inside of the mouth.
Even though they are amazingly small, each human cell has about 2 metres of DNA carefully packaged into it. This DNA is identical in every cell of the human body (with only a few exceptions, such as mature red blood cells which have no DNA at all).
99 percent of DNA is the same in everyone, so there is no point profiling these bits. Instead, only short, highly variable regions of DNA are examined. These are used to create a profile that is unique to each person.
Get information sheet: DNA profiling
The biological samples from individuals destined for the National DNA Databank are discarded after the profile has been obtained, and within three months of being collected. The police may keep other biological samples, such as bloodstained clothing as evidence, which may be profiled at a later date.
Who is in the Databank?
There are currently over 70,000 DNA profiles in the National DNA Databank. The databank includes DNA from three categories:
- Suspects in criminal investigations who have volunteered a DNA sample
- People convicted of certain offences who must provide a DNA sample
- Anyone who has volunteered a DNA sample for the Databank
75-80 percent of crimes reported began as a burglary, and many violent criminals have a history of burglary. Because of this, police have made a concerted effort to collect forensic evidence from the scene of burglaries and from the suspects of such crimes.
Can anyone use the Databank?
Information in the database is protected by the Criminal Investigations (Bodily Samples) Act (1995). Only the police and ESR scientists are allowed access to this information for legitimate purposes.
A crime-solving tool
The National DNA Databank can be used to compare the profiles of samples taken from a crime scene with people on the database, and to compare samples taken from different crime scenes.
So far, ESR has been able to match 58 percent of the DNA profiles from unsolved crimes to individuals profiled on the DNA database. They have also found that 34 percent of the DNA samples from unsolved crimes match samples from other crimes. This was a vital tool in identifying Maureen McKinnel's murderer 14 years after her death.
The Maureen McKinnel case
On Boxing Day 1987, 38-year old Maureen McKinnel was strangled to death in her home in the quiet town of Arrowtown. Four days later, her body was discovered on the bank of the Arrow River.
Around 500 people were investigated, but no suspects could be convincingly linked to the crime.
Maureen had scratched her attacker and traces of his skin and blood were collected from under her fingernails.
In 2001, these samples revealed information they had been keeping secret for 14 years: they gave police a DNA profile of her killer - they just needed to match it to a person!
While police were organising to collect DNA samples from their hundreds of suspects, a man named Jarrod Mangels was arrested in Nelson on a disorderly charge. He spent a night in jail and gave a voluntary DNA sample to the DNA Databank. The sample was sent to ESR for profiling, where it revealed a match with the blood sample found under Maureen's fingernails.
In 2004, Jarrod Mangels was sentenced to life in prison for the murder of Maureen McKinnel. He would have been 15-years old at the time of her murder.
Written by Sara Loughnane, NZ Science, Mathematics, and Technology Teacher Fellow, 2006.
- 16 November 2007