Cannabis Sativa: Hemp Or Drug?

Cannabis sativa: Hemp or Drug?

(Only Dopes Smoke Ropes)

SCOPE Working Group

Eric Ribbens, Mark Bergland, Chi-Cheng Lin

Karen Klyczek, Ethel Stanley

Arizona has legalized growing and selling hemp. Hemp is a subspecies of Cannabis sativa, but instead of selecting for high THC levels hemp growers have chosen varieties that produce long strands of fiber.

Hemp

Drug marijuana

Case A: George

The Arizona state DEA has arrested George Malkay. George has a record of drug abuse, but claims he’s clean. He grows hemp. All legal, but the DEA claims they found 6 bags of dried leaves in his warehouse, bags they think contain high-potency marijuana that, according to an informant, came from Guatemala.

You know how to analyze DNA sequences. You have researched Cannabis, and found that several regions with small tandem repeats (STRs) have been identified in the genome. While you cannot directly measure whether a plant is hemp or drug, it is quite possible to make inferences about geographic differences.

You have DNA sequences from the six samples. You have primers that amplify regions of Cannabis DNA with small tandem repeats (STRs). The length of the STRs identify related varieties.

1) Test the 6 samples, and determine if they are from Arizona or Guatemala.

2) The prosecutor decides that George is guilty because of your findings. However, you disagree. Convince the prosecutor that George is really innocent.

Case B: Bob

3) Bob Propson is a farmer who has become convinced hemp is worth growing. The DEA, in a routine inspection, collects six samples from his farm. Test his samples. Are they all from Arizona?

4) Based on your evidence, Bob is arrested and prosecuted. How do you explain to the jury what you did? Write a persuasive document that explains how the DNA analysis works, what the data mean, and why you believe it demonstrates that Bob is guilty.

5) Bob’s attorney argues that the DNA technology is desperately flawed. In a dramatic challenge, he throws a bag of marijuana on the table, a bag he claims came from a specific but unrevealed location. He challenges you: tell me the location. If you can’t identify the location, you know the jury will let Bob go free. The prosecuting attorney gets Bob’s attorney to tell you the samples are from one of five locations. Run the test, and determine where the samples are from.

Images

Smoker:

Hemp:

Drug:

Intro Photo:

Farmer:

References

Gilmore, S., Peakall, R. 2003. Isolation of microsatellite markers in Cannabis sativa L. (marijuana). Molecular Ecology Notes :105-107.

Gilmore, S., Peakall, R., Robertson, J. 2003. Short tandem repeats (STR)DNA markers are hypervariable and informative in Cannabis sativa: implications for forensic investigations. Forensic Science International 131:65-74.

Bob Case