Even if you're lucky enough to buy from legal dispensaries, the labels on cannabis packaging often bear little relationship to the flower inside. Cannabis' still-illegal status in most jurisdictions, and the hazy rules surrounding naming conventions, often result in the mislabelling, with sativa strains being sold as indicas, and vice versa.

"Even though hemp and marijuana are important crops, knowledge about cannabis is lacking because of its status as a controlled drug," UBC botanist Jonathan Page, who co-led the study, told CanTech. "Cannabis breeders and growers often indicate the percentage of Sativa or Indica in a cannabis strain, but they are not very accurate."

But all of that could soon change, thanks to the efforts of scientists attempting to do for cannabis what 23andMe has done for human genetics.

The process involves analyzing thousands of samples of cannabis-containing tinctures, medicines, fibres, and other artifacts collected from around the globe over hundreds of years. Of nearly 2,000 specimens, 1,500 of them have been entered into a software program that maps out the DNA into clusters and how they're related to one another."Ancient DNA is very fragmented," Jessica Kristof Phylos Bioscience of told Newsweek. "There's maybe 1 percent of cannabis material in these samples, and they're already diluted by whatever buffers that have been added to make it medicinal. Then, on top of that, there's yeast and E.coli and stuff growing on it for years."

Despite the challenges, mapping the cannabis genome is "a quest that could change almost everything we know about marijuana, according to Newsweek's Winston Ross. "At this point, most cannabis is produced in the dark, then sold to recreational consumers and medical patients with catchy labels that are nearly always misleading."

In addition to helping consumers make more informed choices, the project has important implications for our understanding of human history. "Cannabis is one of the few plants carried all over the world, over the past 10,000 years," writes Newsweek's Winston Ross."Tracing its genetics could tell us something we didn't know before about where humans traveled and when."