Identification of unidentified deceased persons now possible through distant relatives

Genealogical DNA testing helps find answers when identifying unidentified deceased persons, such as WWII victims. This involves comparing the DNA profile of relatives of a missing person with the DNA of an unidentified deceased person. However, a standard genealogical DNA test is usually unsuitable when the DNA of a distant relative is used. The Netherlands Forensic Institute (NFI) now uses new technology that looks in greater detail at more locations in DNA. ‘For instance, we recently contributed to finding the name of an unidentified WWII victim.’ 

Grave of an unidentified deceased person. Photo: Cinthia Nijssen | Mediacentrum Defensie

As genealogical DNA specialist at the NFI, Charissa van Kooten focuses on identifying unidentified dead persons. She has been working on determining the identity of WWII victims for several years now. These are the unknown dead exhumed at the Loenen Field of Honour from 2018 onwards. The project run by the BIDKL (Royal Netherlands Army Recovery and Identification Service) and to which the NFI contributes, represents an ultimate attempt to give unidentified war victims back their name. As of today, the BIDKL has exhumed more than one hundred unidentified deceased persons in all. Pieces of bone and teeth have been recovered from the victims, which the NFI used to obtain DNA profiles.

Dutch DNA Database for Missing & Unidentified Persons

Both an autosomal DNA profile (DNA from both parents) and a Y chromosome profile (patrilineal DNA) and mitochondrial DNA profile (matrilineal DNA) were created for one of these unidentified dead persons and included in the DNA Database for Missing & Unidentified Persons. This database is managed by the National Expertise Team for Missing Persons (LOEP) of the Dutch National Police. The NFI conducts DNA analyses and manages the DNA profiles on behalf of LOEP. In addition to the DNA profiles of unidentified dead persons, the database also contains the DNA profiles of close relatives of missing persons, primarily parents, children, brothers and sisters. They allow their DNA profile to be included hoping that a match with an unidentified dead person may be found one day. ‘Unfortunately, the DNA of this specific unidentified dead person did not yield a match in the database’, says Van Kooten. 

At the same time as exhuming the unidentified dead persons, the BIDKL actively investigates who the victims might be and whether any relatives might still be alive. ‘For instance, a nephew of a missing person was found in October 2021. The man was presumed to have gone missing in Berlin in 1944. It was suspected that he might be buried in Loenen as an unidentified person’, explains Van Kooten. This nephew is the son of the missing man’s sister, a matrilineal relative. As such, the nephew and the unidentified dead person should have the same mitochondrial DNA profile (matrilineal line).

Image: NFI
Teeth and pieces of bone are taken from unidentified dead persons. Photograph for illustration purposes.

Inadequate result

A mitochondrial DNA profile had been created using the pieces of bone and a tooth. The unidentified dead person’s mitochondrial DNA profile was compared with the nephew’s mitochondrial DNA. ‘Sadly, the analysis did not yield a conclusive answer’, says Van Kooten. ‘The result was insufficient to exclude or confirm their family relationship and therefore also to generate a DNA link with the missing person.’ 

The investigation risked running aground. Until Van Kooten’s colleagues in the Research team of the Biological Traces division suggested a potential solution: a new method, Qiagen’s Kintelligence kit, which uses Massively Parallel Sequencing. This technology looks at the DNA’s letter sequence, which works even if the DNA is damaged or degenerated. ‘We had only just acquired this technology and had not used it yet. The power of this technology is that you look at many more locations, particularly on the autosomal DNA profile, in a very detailed manner. Where we normally look at 23 locations in the DNA, this method investigates ten thousand locations. Which makes for a much better comparison of persons and allows us to find more distant relatives’, explains the specialist. 

High evidential value 

Van Kooten applied the new technology to the DNA profiles of the unidentified dead person and their potential nephew. ‘I looked at and compared the similarities and differences of both profiles. The software then uses a reference database to calculate how many times more probable the DNA profiles obtained are if the two persons are relatives than if they are not relatives.’ She was overjoyed to find high evidential value: a strong result that they are indeed family. Where all other DNA analyses failed, a new method was able to give this unidentified dead person back his name after 79 years, thanks to his nephew.

Answer for surviving relatives

The new technology is especially useful in cases where a dead person’s identity is suspected but no close relatives remain to perform regular DNA analysis. ‘This technology is a valuable new tool that we can use in our search to identify unidentified dead persons’, says Van Kooten. ‘The BIDKL often makes a huge effort in such cases, including exhuming unidentified dead persons and tracking down relatives of missing persons. So you do not want your investigation to come up empty, that’s very frustrating. If there are living relatives, you want to give them an answer. It’s beautiful that we can now do this in such complex cases.’