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DNA ‘fingerprinting’ technique

SEPARATES HEMP FROM MARIJUANA

HEMP AND MARIJUANA, BOTH MEMBERS OF THE SPECIES CANNABIS SATIVA, LOOK IDENTICAL. THE DIFFERENCE IS THAT MARIJUANA CONTAINS HIGH LEVELS OF THE PSYCHOACTIVE DRUG TETRAHYDROCANNABINOL (THC). CONSEQUENTLY, SINCE 1937, IT HAS BEEN ILLEGAL TO GROW CANNABIS IN THE U.S. THIS HAS PROHIBITED GROWING HEMP—WHICH HAS POTENTIAL ECONOMIC, ENVIRONMENTAL, AND HEALTH BENEFITS—AS A CROP.

Plant biologist George Weiblen hopes to develop a variety of hemp that can be grown in the U.S.

But a new DNA fingerprinting technique developed by George Weiblen, assistant professor of plant biology, and Shannon Datwyler, a former postdoctoral associate, makes it possible to distinguish varieties of Cannabis sativa. Weiblen believes the technique, which relies on genetic markers, may be a first step toward developing a hemp variety suitable for the United States.

“Our goal is to develop a crop alternative for Minnesota farmers,” Weiblen says. There is no annual fiber crop that can be grown in Minnesota. The weather is too cold for cotton. Hemp is very durable and produces its own defense against pests, which is good for the environment. And the seeds, which are rich in healthy fatty acids, can be used in a variety of food products. There’s a growing market in the U.S. for hemp products, but the law requires them to be imported.

Meanwhile, the technique can be applied to marijuana as evidence in criminal cases, which could help identify drug sources and distribution networks. It may also prove useful in countries where growing hemp is permitted but marijuana is illegal, as in Canada and Europe.

The work appears in the March issue (volume 51, No. 2) of the Journal of Forensic Science.

Weiblen, whose research focuses on co-evolution of fig trees and insects in rain forests, became interested in the research because of genetic similarities between fig trees and Cannabis. Because Cannabis has much shorter generations, it provides a good model system for studying the fig genome, much like studying fruit fly genetics helps scientists understand human genetics.

A few years ago, Governor Ventura commissioned a task force to look into the feasibility of growing hemp in Minnesota. Weiblen offered to help. Thus far, he has used a Packard Fellowship to support the work, but he is seeking public or private funding. His ultimate goal is to learn enough about the Cannabis genome to produce a drug-free hemp plant that looks different than marijuana.