Forensic scientists in the US are applying DNA fingerprinting methods to the cannabis plant. They say the technique, which is being used to create a database of DNA profiles of different marijuana plants, will help them to trace the source of any sample, so reports New Scientist. "It links everybody together: the user, the distributor, the grower," says the database's creator, Heather Miller Coyle of the Connecticut State Forensic Science Laboratory in Meriden. "That's the real intent of it, to show it's not just one guy with a little bag of marijuana, but it's a group of people." A method for spotting the tiniest traces of marijuana, based on detecting DNA unique to cannabis chloroplasts, has already been developed in the UK (New Scientist print edition, 7 August 1999). But the profiling method, based on the same principles as DNA fingerprinting of people, can distinguish between closely related cannabis plants (Croatian Medical Journal, vol 44, p 315). In a case awaiting trial in Connecticut, prosecutors plan to use cannabis DNA profiles to show that two apparently separate cannabis growing operations were actually linked. The two operations, in different parts of the state appeared separate until analysis of the plants revealed that some had identical DNA fingerprints, showing that the growers were sharing material. "From the investigative point of view that was phenomenal," says Timothy Palmbach, director of scientific services at the laboratory. Full article here.