Marijuana
A new study looks at marijuana on a genetic level. AFP

As pot and hemp gain steady acceptance in the United States -- four states and Washington, D.C., have legalized marijuana, other states have decriminalized it, more than 20 states approve medical marijuana, and new laws allow hemp to be grown for research -- botanists are looking more closely at the DNA of the plants and their different strains. Looking at weed at the genetic level can help classify and organize strains -- and might further distance hemp from its psychoactive counterpart.

Unraveling the family history of weed and hemp has been difficult because they were illegal for a long time. But botanists from the University of British Columbia recently analyzed the genotypes -- the collective genes -- of 81 marijuana and 43 hemp samples. If you're not up on hemp: When people learned about the industrial value of it, the cultivation of this plant led to a very different breed of plant from its pot counterpart. There's much more diversity in hemp samples than in marijuana samples. Hemp contains trace amounts of the same active chemical, THC -- less than 1 percent -- but there were fears it could get you high and be a way to bypass laws against pot use. Understanding how these plants sequence THC could lead to a strain without THC.

As for pot, the three strains are C. sativa, C. indica and C. redueralis, and it turns out their genetic structure is pretty complex. Misclassification has happened in several cases. A sample labeled as a Sativa strain -- which users claim to produce more of a "head high" with stimulating effects -- was revealed to be genetically identical to an Indica strain -- believed to provide a more relaxing experience. The research showed these strains could be genetically distinguished, but their reported ancestry -- discussed by your friendly medical marijuana dispenser -- may not be so accurate.

"Right now, the genetic identity of a marijuana strain cannot be accurately determined by its name or reported ancestry. Ultimately we require a practical, accurate and more reliable classification system of this plant," Jonathan Page, a botanist at the University of British Columbia and co-lead author, said in a statement. The research was published in PLOS ONE.