Cannabis DNA database a boon to busts

A national genetic database of cannabis samples has been compiled by the Australian Federal Police (AFP), the Australian National University (ANU) and the Canberra Institute of Technology (CIT) to help law enforcement agencies track down cannabis suppliers.

The database of 500 plants seized in busts in five states and territories could help break organised crime rings and identify legal hemp plantations being used as a cover for the production of drugs.

AFP National Manager Forensic and Data Centres James Robertson said the database was the culmination of 15 years of research by the AFP, CIT and the ANU and is believed to be the first of its kind in the world.

“Scientists at the ANU, the AFP and CIT built the database of DNA profiles of the most frequently used illicit drug in Australia from plants grown in fields, hydroponic operations and pots,” Dr Robertson said.

He said the team analysed samples from legal cannabis fibre plantations and published the results in a monograph and in the July edition of the Journal of Forensic Science.

The scientists analysed DNA from root, stem and leaf samples seized in raids in Victoria, South Australia, Western Australia, Tasmania and the ACT over the past few years.

They focused on 10 stretches of DNA called short tandem repeat markers – repeating segments of genetic code written in the letters A, C, G and T.

They demonstrated that there was enough genetic diversity in Australian cannabis to identify individual plants from the 10 markers.

The ANU School of Botany and Zoology’s Dr Rod Peakall said establishing links between the plants was a complex process but said the cannabis program had been a test case for forensic botany.

Dr Peakall said that comparing the DNA sequences pointed to potential links between seizures to help identify crime syndicates.

He has been working to set up the ANU’s new Master of Molecular Genetic Analysis program to meet the growing demand for experts in the field.

He said the database would become more powerful as samples were added but the genetic evidence would have to be combined with other evidence to support a conviction.

“DNA evidence never stands alone, but the database is another tool to be used in the legal process,” Dr Peakall said.

A comparison of DNA of plants in the database showed that some seizures shared DNA profiles, perhaps because they had been grown from cuttings – the main means of propagation in hydroponic operations – which produces clones.

“One complication is selective breeding over decades for plants high in the psycho-active agent tetrahydrocannabinolic acid (THC),” he said.

“Dispersal of seeds and cuttings through the drug subculture has seen the genetic sequences of strong cannabis sweep through the national gene pool, reducing the genetic diversity in drug varieties.

“This could also account for the shared profiles and makes it impossible to pinpoint the state of origin of plants,” Dr Peakall added.

The research was supported by the National Drug Law Enforcement Research Fund. The NDLERF finances research for the purpose of preventing and reducing the harmful effects of licit and illicit drug use in Australian society.

The NDLERF supports research that leads to evidence-based practice in drug law enforcement, is experimental and innovative and enhances strategic alliances between areas of law enforcement, human service providers and research agencies.

A copy of the Monograph, Applications of new DNA markers for forensic examination of Cannabis sativa seizures – developmental validation of protocols and a genetic database, can be accessed from the time of the launch at www.ndlerf.gov.au.