My friend in the forensic science PhD program recently got published for her work on developing a Marijuana STR multiplex system. Marijuana is a prevalent drug related to crime, especially in this area so close to the Mexican border. In 2014, marijuana became legalized in some states for medical and recreational use. Therefore, it has become a challenge to track and prevent legal marijuana from entering states where it is illegal. The goal of this project was to aid in individualization of seized marijuana samples and to link drug cases together. They modified and optimized a 13-loci multiplex (meaning 13 loci can be amplified and sequenced in one reaction) according to guidelines and standards required in forensic science. They also designed an allelic ladder for sequencing and developed and validated a real-time quantitative PCR method for nucelar DNA specific to Marijuana samples. In the end, they were able to generate full profiles from 127 samples part of 11 U.S. Customs and Border Protection seizures and develop a reference Marijuana population database with allele frequencies. Future work includes looking into tetranucleotide markers opposed to the dinucleotide markers and massive parallel sequencing.
Reference:
Houston R, Birck M, Hughes-Stamm S, Gangitano D. Evaluation of a 13-loci STR multiplex system for Cannabis sativa genetic identification. Int J Legal Med (2016) 130:635-647.
I'm always fascinated by anything related to plant DNA. It's actually what got me interested in forensic science when I was a kid, I remember watching an episode of Forensic Files where they solved a murder using the DNA from a tree. I was like, "Whaaaa?" and ever since then, I have loved forensic science. This seems like the only way they could track legal vs. illegal marijuana. Maybe there are other ways that I don't now of, but I bet this is the most accurate.
ReplyDeleteThis does sound like a very interesting technique to track legal vs. illegal marijuana. Maybe one day the entire country will be on the same page regarding marijuana legalization, but for now this is a promising study. Another idea would be to add some marker in all legal marijuana so that when it is seized in states that it is not legal, there will be a way to know if the person has brought it over from a state where it was legal.
ReplyDeleteI knew someone who was working on this 10 years ago, and basically gave up despite the huge funding they were getting to do this. The level of DEA oversight, and required security was way more than the lab really was comfortable with. I'd be interested in seeing how these kinds of data can tell about the development of different strains and how these have historically moved into markets, and also been supplanted by newer strains.
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