How do you know the strain you’re buying is actually, say, Gorilla Glue #4? Sure, dispensaries and growers say that’s what it is. But the truth is, they can’t know for sure just by looking at it. And according to Portland geneticist Mowgli Holmes, the purveyors of Portland’s recreational cannabis are wrong all the time.

“Growers will come to us and think they have something,” Holmes says. “And it will be something totally different. There are many hundreds of highly distinct varieties. But there are lots that are just similar. People have stirred the same pot of stew for decades, recombining genetic traits, so there’s kind of a uniformity now.”

Holmes is the founder of Phylos Bioscience, which aims to take the guesswork out of the market by identifying cannabis strains at the genetic level. Started in 2014, Phylos has amassed a reference database of strains from all over the world, which the firm can now use to tell samples apart with exacting accuracy. The lab processes hundreds of samples a day from Oregon growers; early this year it will move into a brand-new, more prominent lab in Southeast. In the future, Holmes thinks his genetic database will help breeders develop new strains for pest resistance and yield control. Most important for this nascent industry, genetic knowledge can help guide growers toward developing lower-potency strains—a crucial step toward bringing casual users and current nonusers into the recreational market.

But for Holmes, genetic testing is about consumer protection, first and foremost. “Right now,” he says, “if you find something that works for you, you can never go back and get it again. You don’t know [what you’re buying].”