Though cannabis’s wild beginnings remain unknown, by looking at the plant’s genes, scientists can identify its closest living relative. “Hops, which we use for beer, is the closest existing species to cannabis,” says Cornell University Emerging Crops Specialist Daniela Vergara. Plant geneticists estimate that some 28 million years ago, cannabis and hops plants diverged.

Today, cannabis contains special compounds called cannabinoids that its relatives lack. Two of these compounds are THC, which results in a high, and CBD. The development of cannabinoids may have helped protect cannabis from UV light or from being eaten, though researchers aren’t yet sure. Some ancient communities, including the Chinese, Romans, Greeks, and Indians, utilized cannabis for medicinal and industrial purposes.