THE powerful forensic techniques developed to identify victims of the September 11 terrorist attacks and the tsunami are about to be used for another worthwhile purpose: reuniting Jewish families separated by the Holocaust.

The DNA Shoah project, announced last week in Nature magazine, will be one of the most ambitious pieces of DNA detective work ever. It will attempt to build a database of the DNA of the 300,000 known Holocaust survivors, scattered across the world. DNA "fingerprinting" has often been used to trace the history of peoples, but never on such a scale.

The founder of the DNA Shoah Project is Syd Mandelbaum, a historian and forensic scientist whose parents survived the Holocaust, or Shoah, as it is known in Hebrew.

It was Mandelbaum who, in 1994, headed the American team which used DNA sequencing to disprove the relationship of Anna Anderson Manahan to the Czar and Czarina Romanov, in her claim to be Anastasia. This landmark case became the first to use DNA to solve historical mysteries.

Alongside him will be another pioneering DNA historian, Michael Hammer, a geneticist from the University of Arizona. It was Hammer who co-authored the paper which used Y-chromosome analysis to show that present-day Cohanim - Jewish high priests - are descended from a single male ancestor.

The duo, aided by the US Holocaust Memorial Museum in Washington DC, aim to start collecting cheek swabs from survivors. As the database grows, they will begin to look for matches with DNA samples taken from the remains of unidentified Holocaust victims that have recently started to surface in Poland, Germany and elsewhere in Europe.

The DNA Shoah Project will also use the data to reunite some of the roughly 10,000 Holocaust orphans who were sent abroad after the war to countries including Britain, the United States and Israel.

Mandelbaum explains: "The project will unite loved ones and further establish closure for families who have missing relatives. Most of the six million Jews who were murdered were not cremated but buried after their death in unmarked mass graves.

"Remains of Holocaust victims continue to surface throughout Europe because of continual land development, but, until this project, there was no way positively to identify the victims."

Identifications will be far from easy. Having been buried for more than 60 years, the DNA of victims will be severely degraded. And, even where a fingerprint can be yielded, there may be very few relatives alive for comparison - in many cases, the Nazis murdered entire families.

To overcome these difficulties, the pair will employ powerful forensic techniques that arose from the ashes of the September 11 terrorist attacks. At the World Trade Centre, where some 2700 died, fire degraded the DNA so badly that standard "fingerprinting" could not yield a match.

To overcome this, the investigators turned instead to mitochondrial DNA - which is more abundant and more hardy than the nuclear DNA commonly used in fingerprinting. In addition, they analysed another type of genetic marker - SNP - which relies only on short sequences. But neither of these techniques alone was sufficient to identify most remains.

In search of a solution, the US government approached Howard Cash, president of bioinformatics firm Gene Codes, based in Michigan. The challenge it set was to create software that could integrate both types of DNA fingerprinting techniques, with other more traditional forensic information.

The result was a system known as M-FISys. On the first day it was used - December 13, 2001 - it made 80 matches, which helped identify 55 victims of the terrorist attacks. In total, 1598 of the victims have now been identified.

M-FISys was later used to identify victims of the tsunami, a disaster that presented further challenges. Entire families were lost, leaving no frame of reference, and their personal belongings, which could have provided comparative DNA samples, were simply washed away with their homes. As a result, software which can match the DNA of dead people with each other is now under development by experts at the University of Queensland.

The M-FISys software will now be employed to handle the Shoah data. The race is on to sample the 300,000 survivors - who have an average age of 81 - before it is too late.

Mandelbaum is appealing for people to come forward - pre-war immigrants, survivors, second and third generations of survivors' families. There is a nominal cost related to the testing, but that is unlikely to deter the tens of thousands of survivors who have lived their lives in isolation from their families, their history and their identity.