Matching offers best hope

Dr Sally Ann Harbison, science leader at the ESR.

At a laboratory in Bangkok, young Thai scientists are processing thousands of body samples to extract DNA.

Dr Sally Ann Harbison, science leader at the ESR, has just returned from helping them streamline systems and teaching them where you can cut through teeth and bone and where you can't.

The aim is to get through as many samples as they can, as quickly as they can.

"They're a very young lab, they've not been operating very long," she says.

The samples are from Thai tsunami victims and the lab, just one of many involved with identification processes, is also processing samples from relatives.

DNA matching has not yet started and Harbison expects no one will ever know the identity of some of the victims.

"The scale of the problem is huge," she says.

"It occurred to me on the flight home that particularly in Phang Nga [Thailand's worst hit area] there are bound to be a large number of Burmese. How on earth will we ever identify them?"

A lot of Burmese people are itinerants who cross illegally into Thailand and no family samples are provided for them.

"So there will be a number of bodies for which there will never be an answer."

As well, thousands of bodies have already been cremated.

In the early days of the disaster, when bodies were still reasonably intact, many of the Thai victims were recognised.

So many were cremated in ensuing days that the crematorium, which had been used non-stop, broke down and had to be replaced.

If mistakes were made, they will not now be discovered.

But for decomposing bodies, DNA is the answer.

Harbison says extracting DNA from samples and relatives is the easy part, except for the sheer volume.

"The tricky bit is interpreting the DNA results at the end, and in some ways that's because of the volume as well - and the fact that for so many of them we won't necessarily have reference samples," says Harbison.