I was deep into a longish story about pot potency last week when I was surprised to see an unchallenged assertion that today’s marijuana is GMO, or a genetically modified organism.

I thought that question was settled by the Pulitzer-winning truth-checkers at Politifact. Last year Politifact took on Patrick Kennedy, a spokesman for Smart Approaches to Marijuana (SAM), a national group opposed to legalizing weed. Kennedy came under scrutiny for saying modern marijuana is genetically modified and much stronger than what Barack Obama smoked as a teenager. Politifact agreed that pot potency had increased, but said Kennedy’s claim about genetic modification didn’t hold up.

“The most off-base part of Kennedy’s claim is that the rise in THC levels comes from ‘genetic modification,” said Politifact. “It’s actually from genetic selection, a very old process of producing desired traits from crops.”

Genetic modification or genetic engineering, Politifact explained, involves altering a substance’s DNA at the molecular level, often by adding genes from an unrelated species. (Adding, for instance, an insecticidal protein to corn to build resistance to the European corn borer.) Genetic selection involves breeding plants with the highest concentration of THC. Unlike genetic modification, selective breeding has been practiced for centuries, with crops and animals (think of apples and dogs).

Legally grown in a Seattle warehouse, this plant is selectively bred but not GMO.

But the issue was raised again by SAM’s day-to-day leader, Kevin Sabet, in the NBC story about potency. Sabet flatly asserted “that marijuana is a GMO product just like other products sold by big business.”

I was further surprised that Sabet stuck to his claim, emphatically, when I reminded him on Twitter about the Politifact findings. https://twitter.com/KevinSabet/status/579990287390507008

I wondered if Sabet knew something I didn’t. I got busy reporting, reaching out to experts. Here’s a summary of what they said: Pot is not genetically modified in the gene-splicing sense that scientists and many others mean when they use the term. But selective breeding by pot growers can be called a kind of genetic modification — though it’s more a matter of rhetoric or semantics than accepted science.

Sabet’s quote is good for scaring liberals inclined to legalize weed but ban GMOs. It’s good strategy for trying to peel off some anti-GMO voters in states, such as California, expected to consider legalization next year. And it was bad reporting by NBC, I thought, not to check his assertion. When I pushed back, Sabet responded with sketchy evidence. First, he offered links to two websites. One was a Canadian seed-selling company that featured a joint-smoking Sasquatch on its website. The other concerned an Italian researcher who found a trace of foreign matter in one pot sample that she thought could possibly indicate GMO. Others chimed in on Twitter criticizing Sabet’s understanding of GMO — or his willingness to play loose with the term. But he remained steadfast, this time offering another bit of weak evidence, a link to a piece by a pot advocate in a pro-pot website.

Criticism of Sabet culminated in a bruising piece by Tom Angell of the Marijuana Majority. Others took a gentler approach, with one commenter saying to Sabet: “Your #GMO claims puts all your other arguments in a bad light. #BigPot needs a rational #watchdog.”

Rather than addressing the GMO issue, Sabet shifted to mocking Angell in a tweet and asking why I wasn’t inquiring about something Angell apparently once asserted about Bill O’Reilly.

Here’s what I got from the three experts I contacted.

First to respond was Dr. Mahmoud ElSohly who runs the federal pot farm at the University of Mississippi’s Marijuana Research Project. In an email, I asked Elsohly if today’s pot was selectively bred rather than genetically modified.

“The answer is yes, mostly genetic selection and special harvesting of the buds with almost no large leaves,” ElSohly replied.

Next to respond was George Weiblen, professor of plant biology at the University of Minnesota. Weiblen has researched cannabis genetics. “As far as I know, the varieties of marijuana on the market today have been modified genetically by humans through plant breeding and artificial selection on existing genetic variation
including spontaneous mutations,” Weiblen said in an email.

“Most geneticists seem to distinguish this traditional form of modification from transgenic organisms, where a gene from one species has been transformed using modern biotechnology into the genome of another species that is perhaps not even remotely related,” Weiblen continued. “Transformation of Cannabis in the biotechnological sense has yet to be achieved to my knowledge.”

“Cannabis has been and continues to be genetically modified by humans. The same is true for all domesticated plant species. I’m not surprised
that advocates or critics of marijuana legislation would attempt to use this fact to the advantage of either position but this is rhetoric and not science,” Weiblen concluded.

Lastly, I heard from Charles Davis, a biology professor at Harvard. (Disclosure: I audited Davis’ Plants and Human Affairs class at Harvard last year.) Davis noted that “semantics is at play here in the definition of GMO.”

“It’s too bad the contrarians have twisted things so badly,” Davis continued in an email. “Maybe the counterpoint would be to say that of course we are genetically manipulating Cannabis, but that such manipulations are not much different from those that have taken place over centuries by humans.”

PS: I’m sorry this reads like a debunking. Not my intent. I wanted to explain the GMO issue because it keeps popping up. Unchallenged, unexplained, uncertain in meaning.