One of the roles of the Victorian State Coroner is to determine the identity of any deceased person who dies of unnatural causes or where the cause of death is unknown. 

Identification may be achieved by a number of methods;

• visual identification by family or friends
• circumstances
• fingerprints
• dental records
• DNA testing

DNA identification is particularly useful when the person has been involved in a fire or vehicle accident or if the body is decomposed.  In such circumstances other methods are often impossible and DNA provides the only means of establishing the identity of the deceased.

DNA testing at the VIFM is performed by one of two methods, depending on the circumstances: 

• nuclear DNA testing
• mitochondrial DNA testing.

In some cases it is not possible to analyse nuclear DNA, for example with skeletal Nuclear DNA Testing

The preferred method of DNA testing for identification is basically the same as the analysis carried out for paternity testing.  This method involves comparing the DNA profile of the remains with the profiles of known relatives.  Once the Coroner's office has determined a possible identity of the deceased, relatives can be contacted to provide a small blood sample for comparison.  This may involve testing the person's mother and father to determine whether deceased is a child of these parents.  If there is a match between the DNA profile of the deceased and those of the parents then it is likely that the deceased was in fact their child and an identification can be made.  Children of the deceased, or brothers and sisters can also be compared if parents are not available for testing.

In some cases it may be possible to compare the DNA profile of the deceased with a profile from a sample known to have come from the person believed to be dead.  Samples that may be used for this type of comparison include biopsy tissue specimens from medical procedures, some hair samples known to be from the person, and Guthrie spots.  A Guthrie spot is a sample of blood collected by a heel prick method soon after birth for enzyme analysis.  All children born in Victoria since the late 1960s have had such a blood sample collected and stored on a paper-like card known as a Guthrie card.  These cards are stored by hospitals for a number of years.  It may be possible for the Coroner to obtain permission to use these cards for DNA testing in identification matters.

A direct comparison of a sample from the remains and the antemortem sample will indicate whether the DNA profiles match.  If they do, it is likely that the deceased has been correctly identified.  If the profiles are different, then the investigation must continue. 

In some cases it is not possible to analyse nuclear DNA, for example with skeletal or badly decomposed remains.  Another type of DNA that can be analysed is mitochondrial DNA.   One major difference between nuclear and mitochondrial DNA is that there is only one copy of nuclear DNA in each cell, but there can be up to 1,000 copies of mitochondrial DNA.  As a biological sample ages, the DNA is gradually broken down (degraded) into small pieces that are not suitable for DNA analysis.  Due to the multiple copies of mitochondrial DNA it is quite likely that enough DNA strands will have survived to perform successful DNA testing.

Mitochondrial DNA is inherited solely from the mother.  Therefore each child of a particular woman will share her mitochondrial DNA sequence, which will also be the same as all the mother's brothers and sisters, her mother and all other relatives along the maternal line.  This means that a match in the DNA sequence indicates that the deceased person is likely to be a member of that family.  This evidence can assist the Coroner in making a positive identification of the deceased.  Obviously, this method cannot be used to distinguish between more than one deceased person from the same maternal line.

Both of these methods of DNA testing can provide information that can be used to identify human remains.  Reliable results of nuclear DNA testing can often be completed within 24 hours of samples being received.  Mitochondrial DNA testing usually takes a week.

An example of the use of DNA testing in a disaster

The crash of TWA Flight 800 off the east coast of the USA in 1996 resulted in the deaths of 230 people.  Since identification by other methods was not possible, the investigators turned to DNA testing.  Using this technique they were able to positively identify almost all of the passengers on the plane.

DNA analysis can provide fast, reliable identification of human remains.   There have been cases where alternative methods of identification have been unsatisfactory.

On November 17th 1997, 58 tourists were killed by Islamic militants in Luxor, Egypt.   Identification of the bodies was performed visually by the tour operators.   Upon return of the bodies to their families for burial it was discovered that several had been identified incorrectly.  One unfortunate family in England had received two mistakenly identified bodies instead of their family members.  One of these bodies was located in Switzerland, the other was still missing two weeks after the killings (BBC News, November 29th 1997).

There are also examples in Australia where reliance on circumstantial evidence to identify remains has led to mistaken identification.  In September 1994, our laboratory received two bones from a skeleton which had been found in Western Australia in 1987.  Based on the identification of clothing and jewellery, the police believed that the remains belonged to a young woman who had disappeared in 1977 and were prepared to recommend positive identification to the Coroner.  However, with the availability of new techniques, it was decided to confirm the identity by DNA testing.  Comparison of the DNA profile of the bone with the missing woman's parents showed, unexpectedly, that the remains were not those of their daughter.  Police in the Northern Territory became aware of the case and presented a sample from the sister of another woman who was missing.   DNA tests showed that the remains were likely to have been those of the second missing woman.  Clearly, circumstantial evidence in such cases cannot be considered sufficient for a positive identification.

The benefits of DNA testing in situations like these are clear.  DNA testing already provides the most definitive method of identification within a relatively short time.  With continual advances in technology it is likely that DNA testing will become even faster.  As people become aware of the power and speed of DNA testing this technology should be used more and more widely   for identification purposes.