July 6, 2009 – Just as blue eyes and stubborn spirits are genetically inherited from parents, botanical genes code for flower color, seed shape, and stem size as well as the production of molecules important for fragrance, flavor, and natural chemicals.
Cannabis sativa, a plant cultivated for thousands of years, contains a genomic region responsible for the production of the psychoactive chemical, tetrahydrocannabinol (THC). It is this chemical that earned Cannabis its illicit label, “marijuana,” and motivated United States lawmakers to outlaw Cannabis cultivation over seventy years ago. The resultant debate to legalize Cannabis stems from social, political, and economic issues that, quite possibly, only modern science can ameliorate.
“I can’t think of another plant that is so regarded as a miracle by some and a menace by others,” said George Weiblen, Professor of Plant Biology at the University of Minnesota, in a recent interview.
“Today, Cannabis research in the United States focuses almost entirely on marijuana’s effects on the human body,” Weiblen noted. “I’m one of very few researchers permitted by our government to study the plant. What our research has discovered will challenge opinions on either side of the controversy.”
Depending on the cultivar, or plant variety resulting from selective breeding, Cannabis plants vary in THC concentration and are generally categorized as either hemp or marijuana. Hemp is primarily harvested for durable fiber, isolated from the plant stems, and produces a minimal amount of THC (0.3 percent). Marijuana, on the other hand, contains higher percentages of THC (between 2 and 25 percent) and is typically used for medicinal and “recreational” purposes.
“The problem is that hemp and marijuana are difficult to tell apart based solely on appearance. They can only be distinguished by their THC concentrations,” explains Weiblen. “For this reason, federal lawmakers are reluctant to relax legislation and permit hemp cultivation on domestic soil.”
Cannabis took root in America during the 16th century where it was legally grown to produce essential materials — paper, clothing, canvas, and rope — for nearly 400 years. Additionally, Cannabis seed oil gained popularity as a nutritional, cosmetic, and industrial commodity, and THC was discovered to treat medical conditions, including pain, nausea, appetite loss, and glaucoma. In 1937, all forms of Cannabis became illegal to grow in the U.S. with the passing of The Marijuana Tax Act.
Even today, hemp products must be imported. However, the global trend toward biofuels and renewable resources, and the search for better therapeutics have launched Cannabis into the spotlight as an attractive cash crop.
“Cannabis is an ideal alternative for farmers to grow on marginal land. As opposed to cotton, it yields large quantities of durable fibers, survives northern climates, and is resistant to pests and disease,” says Weiblen.
So how can science contribute to the production of a Cannabis variety not to be confused with marijuana in appearance or THC concentration?
Enter Weiblen and his team of plant biologists. They have utilized a scientific technique called DNA “fingerprinting” to identify distinct DNA sequences, or “markers,” that distinguish hemp from marijuana. The process requires a very small Cannabis sample and only few days, making it a highly functional forensic tool with utility in economic and political fields.
Weiblen and his researchers are also just a few genes shy of cracking the entire “cannabinoid genome,” a feat that will help pave the way to a completely drug-free, legal, Cannabis plant.
“My research brings honesty and scientific facts to the debate that hopefully one day will aid in sound legislative decisions,” he concludes.