DNA profiling could identify key players in illegal drug trade

DNA profiling technologies are rapidly advancing, creating the potential to identify individuals involved in making, packing and transporting illegal capsules by analyzing the exterior of the illicit drugs and the ziplock plastic bag in which they are carried.

Experiments carried out by Flinders University forensic science experts found DNA accumulates in different areas, depending on an individual's involvement in the process, which could aid identification of people involved in the drug-making and trade. 

The study also found DNA from the surface of capsules can be transferred to the inner surface of ziplock bags commonly used in transportation.

"This small-scale study indicates that capsule packers deposit less DNA than capsule makers, who spend more time handling the drug casing, and those that make the capsules can leave enough DNA for a complete profile with as little as 30 seconds of contact," says Flinders PhD candidate Madison Nolan, lead author of a new article in Forensic Science International: Genetics.

As well, the DNA yield on these commonly used plastic bags is higher when handled by several people compared with little-to-no contact.

"Generating informative DNA profiles from the inside surface of the ziplock bag could be more useful than the outer side, as could be testing of other 'protected' areas of the bag such as the zip or inner edge of the seal," says Ms. Nolan, from the College of Science and Engineering.

Co-author Professor Adrian Linacre says illicit substances frequently distributed in secure ziplock bags can be seized by police and tested by forensic investigators.

"This study will guide investigators in the area of the bag that might be most informative when sampling the bags for DNA, and the potential for secondary transfer onto the inside surface of storage containers from the capsules themselves," says Professor Linacre.

"Strong DNA profiles were generated for the individual who made the capsules and for the individual responsible for packing the ziplock bag."

Covered by ethics committee approval, the study used three participants – described as heavy and intermediate DNA shedders – to 'pack' gelatine capsules with a powder. Before starting the experiment, the bags were sterilized to minimize the amount of DNA on the exterior, and participants respectively washed or did not wash their hands before capsule making. 

The ZLBs were sampled for DNA on the inside, the inner semi-protected portion of the opening, and the outside surface. The exterior of capsules was also sampled along with a storage container.