DNA Photofits from dandruff, skin and sweat DNA

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BALDING CRIMINALS with dandruff, sweaty palms or sunburn should be very, very worried. The police are on the verge of a forensic breakthrough that would have left even Sherlock Holmes gasping: the creation of Photofit faces from the DNA of cells left at the scene of a crime.

A flake of dandruff or a hair will soon be all that is needed to depict the colour of the suspect's eyes, hair and skin, whether they have a full or a long face, and even the shape of their earlobes.

Once a match is made, wriggling out of a conviction could be almost impossible. Modern DNA techiques offer only a one in a billion possibility of being wrong if the DNA of a suspect matches that found at the scene of the crime.

The work is part of joint research by scientists at the Forensic Science Service (FSS) and University College London (UCL) to enlarge the range of DNA profiling techniques. They can already advise police on the likely race of the criminal, based on just one cell from the blood, hair, or even skin cells left behind from sweaty palm prints. Now, Peter Gill of the FSS wants to make one of the biggest steps ever in forensic science. "We will be able to use DNA to much greater effect," he told the British Association of Science festival at Sheffield yesterday.

"We could give information about the skin, eye, hair colour, and the facial characteristics. Once we know exactly which genes are involved, we can pass that on to the investigation," added Mr Gill.

Hair and eye colour are closely linked: it would be quite easy to spot whether somebody had the gene for blue eyes, as two copies of the gene are needed.

The shape of earlobes is strongly inherited, indicating that their shape is genetically determined even though they are just flesh. The same is generally true for the shape of a nose or a chin.

Dr Gill reckons it will be about ten years before his vision is realised, but he is confident that information from worldwide research like the Human Genome Project - which aims to map all of human DNA - will provide the data he needs.

Meanwhile the sites from which DNA can be picked up is growing. Research in the West Midlands has extracted useful samples left by car thieves on steering wheels. The work revolves around the Home Office's National DNA database, launched in 1995, which contains 600,000 DNA samples from convicted criminals and the scenes of unsolved crimes. Every year another 200,000 samples are added, and the price of carrying out DNA profiles is plummeting. So far, 50,000 matches have been made with suspects to solve crimes.