Thursday, June 10, 1999 Published at 11:16 GMT 12:16 UK
DNA hides spy message
The DNA trace reads "June 6 Invasion: Normandy"
Espionage has embraced biotechnology with the creation of a microdot which conceals secret messages in the immense complexity of human DNA.
The first message sent using the new technique pays tribute to the original photographic microdots used in World War Two. It reads: "June 6 Invasion: Normandy".
"Masterpiece of espionage"
The researchers proved the DNA microdot works by pasting the tiny dots over the full stops in a typed letter, posting it and then analysing the dots when it arrived back. The message was received, loud and clear.
Catherine Taylor Clelland, at Mount Sinai School of Medicine, New York, told BBC News Online that the DNA microdot team had not yet been approached by the FBI.
"But we did wonder if we would get security clearance to have the paper published in the first place," she said.
Message in a marker
The first step of the technique is to use a simple code to convert the letters of the alphabet into combinations of the four bases which make up DNA. Next a piece of created.
Next, a piece of DNA spelling out the message is synthetically created. It contains the secret message in the middle, plus short marker sequences at each end.
This is slipped into a normal piece of human DNA.
"To try and identify it within that complexity, when all the strands appear absolutely identical would be, we think, virtually impossible," says Dr Taylor Clelland.
The key to unravelling the message is knowing what the markers at each end of the DNA message are. These allow the message recipient to use a standard biotechnology technique, the polymerase chain reaction, to multiply only the DNA which contains the message.
This DNA can then be sequenced and the message read.
The team included Professor Carter Bancroft and Viviana Risca and is published in the journal Nature.