SOURCE: Minnesota Public Radio
A University of Minnesota plant biologist has identified a key gene that distinguishes hemp from marijuana. George Weiblen is one of only a few scientists in the country who has been granted a waiver on a federal law prohibiting hemp.
He joined MPR News’ Tom Weber to discuss the significance of his discovery.
What are the similarities between hemp and marijuana?
They’re members of the same species. They belong to the genus cannabis and they are distinguished by the concentration of the psychoactive drug, which is abundant in marijuana and much less so in hemp.
What did you find in this gene?
What we did was take advantage of this diversity that exists within the species cannabis to cross a marijuana plant with a hemp plant.
And then [we mapped] the gene that distinguishes the production of THC versus a related molecule, called CBD, that’s been getting a lot of attention in the press lately.
We can trace this down to the fact that marijuana is missing an enzyme that produces this molecule, CBD, so THC dominates in the chemistry of marijuana plants.
So: Marijuana has more THC than hemp — and hemp has more CBD. But why?
We knew how they were different; that comes as no surprise to anyone, but why are they different?
What happened in the history of humans growing cannabis plants to allow for a plant in which THC is so dominant?
We believe we’ve identified the genetic changes that made that possible and how humans have selected for marijuana potency.