Weeding out marijuana: Researchers close in on engineering recognizable, drug-free Cannabis plant

September 15, 2009,

In a first step toward engineering a drug-free Cannabis plant for hemp fiber and oil, University of Minnesota researchers have identified genes producing tetrahydrocannabinol (THC), the psychoactive substance in marijuana. Studying the genes could also lead to new and better drugs for pain, nausea and other conditions.

The finding is published in the September issue of the Journal of Experimental Botany. Lead author is David Marks, a professor of plant biology in the College of Biological Sciences.

The study revealed that the are active in tiny hairs covering the flowers of Cannabis plants. In marijuana, the hairs accumulate high amounts of THC, whereas in hemp the hairs have little. Hemp and marijuana are difficult to distinguish apart from differences in THC.

With the genes identified, finding a way to silence them—and thus produce a drug-free plant — comes a step closer to reality. Another desirable step is to make drug-free plants visually recognizable. Since the hairs can be seen with a magnifying glass, this could be accomplished by engineering a hairless Cannabis plant.

The researchers are currently using the methods of the latest study to identify genes that lead to hair growth in hopes of silencing them.

"We are beginning to understand which genes control hair growth in other plants, and the resources created in our study will allow us to look for similar genes in Cannabis ," said Marks.

"Cannabis genetics can contribute to better agriculture, medicine, and drug enforcement," said George Weiblen, an associate professor of plant biology and a co-author of the study.

As with Dobermans and Dachshunds, marijuana and hemp are different breeds of the same species (Cannabis sativa), but marijuana contains much more THC than hemp, which is a source of industrial fiber and nutritious oil.

Hemp was raised for its fiber — which is similar to cotton but more durable — in the United States until legislation outlawed all Cannabis plants because they contain THC. Today, marijuana contains as much as 25 percent THC, whereas hemp plants contain less than 0.3 percent.

Hemp was once a popular crop in the upper Midwest because it tolerates a cool climate and marginal soils that won't support other crops but, after drug legislation, hemp fiber was replaced by plastic and other alternatives. Recent popular demand for hemp products has led some states to consider the economic and environmental benefits of hemp. North Dakota legislation aims to reintroduce it as a crop, and Minnesota is considering similar legislation. At the same time, California and other states permit the medicinal use of .

"I can't think of a plant so regarded as a menace by some and a miracle by others," says Weiblen, who is one of the few researchers in the United States permitted to study Cannabis genetics. In 2006, Weiblen and colleagues developed a DNA "fingerprinting" technique capable of distinguishing among Cannabis plants in criminal investigations.

Source: University of Minnesota (news : web)

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5 / 5 (4) Sep 15, 2009
We already have THC-less cannabis, it's called hemp. As referenced in the article itself. I noticed no reference in the article as to why removing the THC from non-hemp cannabis is beneficial, other than perhaps learning more about the genes. Why is removing THC advertised as the main story?

Oh wait, here's the ticket:

"Cannabis genetics can contribute to better ... drug enforcement,"[/quote] [/blockquote]
Sep 15, 2009
This comment has been removed by a moderator.
Sep 15, 2009
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3.7 / 5 (3) Sep 15, 2009
Actually, characterizing the genes responsible for THC production in Cannabis is extremely useful, as an enterprising genetic engineer could splice them into other plants - imagine the fun of adding them to the Oak or Maple genomes, for example! Then just toss another log on the fire and High-Ho! Add them to Oregano for some High-talian cuisine, or to mung beans for some C-High-nese food.
4.5 / 5 (2) Sep 15, 2009
Why remove a natural molecule from a plant? THC has been shown to be beneficial in many ways (hell, I see articles on physorg monthly, claiming new benefits THC might have.) Not to mention that between alcohol and marijuana, the comparitive impacts on health are astronomical.
You don't see studies showing how we can make alcoholess gin, do you?
Idiotic, nothing less.
not rated yet Sep 15, 2009
Maybe the time is right for this to pass but it was lobbying by the petrochemical industry that made even the non-smokable hemp illegal. It's kind of ridiculous it took decades to wait for genetic engineering to make this acceptable since breeding methods likely could have produced a THC free hemp crop long ago. I'm very curious to see if the DEA fights them on this or not (they may argue other cannabinoids remaining in the plant still leave it in its regulatory status).
5 / 5 (1) Sep 16, 2009

...says Weiblen, who is one of the few researchers in the United States permitted to study Cannabis genetics

This gives a pretty clear picture of how insainly stupid the prohibition is. The plant can't be studied properly because all that cannabis research has done so far is to show how incredibly useful and beneficial this plant is.
not rated yet Sep 16, 2009
Well I think that a good approach might be to find the genes in the Pyrethrum daisies which give rise to insecticide molecules [pyrethrins] and put some of these into the Cannabis sativa genome. I know this sounds quirky but we really do need to get hemp growing over vast tracts of land on different continents to provide fibre crops, for all the obvious economic and industrial benefits.

There are other potential benefits however. For example in the south west of Western Australia where I am, the removal of so many trees over the last century has caused a shocking rise of salt laden water tables. These areas were called "wheat belt" before but in many spots now pose an enormous challenge. [Fact: a couple of the rivers flowing out of these areas are now saltier than the sea!]

Well NOBODY is going to persist in smoking stuff that tastes like shit and kills flies out of the air around them. But in WA where flies queue up to buzz into your mouth, to harvest a crop without flies? Beauty!

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