You need genetic authentication to get specific information on cannabis strains. And getting that genetic information may not be available now—or for years to come.

You buy your favorite cannabis strain—let’s say it’s Blue Dream. It’s a common strain, very popular and available at many dispensaries no matter where in the 33 states you go to get it.

But a lab check will tell you that the Blue Dream you got in Denver is not the same Blue Dream you got in Chicago. There may be little changes in the chemical composition. There may be big changes. Or there may just be downright deceit: “Hey, Blue Dream is popular, let’s slap a label on this generic preroll of indistinguishable origin and call it Blue Dream and voila, sales increase!”

Only a lab analysis can show you the cannabinoid and terpene combinations of a specific strain of marijuana that can help you get what you want. Most responsible dispensaries have that information.

But that only gets you close to what you want. You need genetic authentication to get more specific. And getting that genetic information may not be available now—or for years to come.

That unknown is a quiet, ongoing problem with cannabis cultivators and sellers—making sure the consumer gets the strain they want. It has been the sort of Holy Grail that, according to one study, has been “confounded by many cultural factors” because the cannabis plant “has seen wide geographic dispersal and artificial selection by humans over thousands of years.”

Clearing up the genetic structure of a certain cannabis strain is top of the agenda for researchers. The cannabis genome has been sequenced. But researchers say that hasn’t helped with the confusion about what is truly in the plant, and where it originally came from.

To get closer to answers, let’s do a little CSI.

It all started on a Tuesday millions of years ago, in the Pleistocene era. The species of cannabis sativa is thought to have begun during that period in the upland valleys of a mountain range in central Asia, with domestication following a few million years later in the same area.

It has been generally agreed on that the cannabis plant spread alongside the development of humanity.

But the plant has a history of being uncontrollable. Cannabis sativa is a wind pollinated plant, with evidence of cannabis pollen traveling across the Mediterranean from North Africa to southern Spain.

Recreational cannabis appeared in the 19th century in the Magdalena River valley in the Columbia Andes, at various coastal ports, and in Panama during the construction of the canal in the early 20th century.

Photo by Zummolo/Getty Images

In 2003, a formal excavation of a shaman tomb in the Yanghai Tombs near Turpan, Xinjiang-Uighur Autonomous Region, China, revealed the oldest evidence of C. sativa cultivated specifically for its psychoactive components.

According to classic Chinese literature, Shen Nung (ca. 2800 BCE), a celebrated herbalist and patron divinity (whose name literally means “Divine Farmer”), was the first to instruct his people to cultivate hemp. He also prescribed it for medicinal purposes.

Also in 2003, a genetic study of cannabis concluded that cannabis is derived from two major gene pools in Central Asia, but there was insufficient evidence to make an accurate determination. Evidence also suggests the domestication of cannabis sativa could have occurred in more than three areas in Eurasia.

Researchers say that there is immense genetic diversity in the plant that is thought to be divided into four main gene pools: 1. Narrow Leaf (European) Hemp (NLH; C. sativa sativa), 2. Broad Leaf (Chinese) Hemp (BLH; C. sativa chinensis), 3. Narrow Leaf Drug-type (NLD; C. sativa indica), 4. Broad Leaf Drug-type (BLD; C. sativa afghanica).

Another study about cannabis and genes found that the “progenitor-derivative relationships” in cannabis (meaning the original species of the plant and a separate species that diverges from this ancestor) “are yet to be well understood. Until an extensive amount of additional sampling and subsequent genetic analysis on introgressive hybridization is completed, the precise cannabis genetic–geographic data will remain unsettled.”

There you go: Nobody knows what this plant is made of, really, and are trying to figure out what to do with all of this information. Meaning: Your Blue Dream might as well have an asterisk by it *… Blue Dream-esque.

An article in a cannabis science magazine called for the cannabis market to get motivated and “raise the bar on cannabis classification,” stating:

“Regulators should institute broader chemical profiling, genotyping and mandatory cannabis cultivar registration with specific criteria required to grow the cultivar,” the author wrote. “The first step toward standardization in cannabis strain naming would be to throw out the current unregulated model and replace it with the horticultural and agronomic convention of cultivar names. Blue Dream would become Cannabis Sativa cv. Blue Dream. The second step would be to associate a referenced chemotype and genotype with Cannabis Sativa cv. Blue Dream. The combination of the Blue Dream cultivar name with its chemotype and referenced genotype would authenticate it.”

Photo by Shannon Fagan/Getty Images

Sounds reasonable. And complicated. And maybe too much too late. Will it happen? Doubtful.

Still, answers may be forthcoming from the University of Boulder and their Department of Ecology and Evolutionary Biology, or the Cannabis Genomic Research Institute (CGRI), which was begun by Nolan Kane, a professor from the University of Boulder.

CGRI is working on building an ultra-high density genetic map of cannabis; developing analytics to figure out the history of cannabis; and discover hybrid origins of various strains.

The group’s is in the process of sequencing “numerous pure C. sativa, C. indica, and C. ruderalis accessions and heirloom varieties to develop our understanding of the relationships among the major lineages within the genus, the spread of cannabis throughout the globe, and rates of historical hybridization between the named species. This will help identify important genetic variation that could be used for breeding purposes, as well as answering basic science questions about the genus, such as its origins and taxonomic classification, which is a topic of controversy among biologists.”

Your choice here is to keep getting the strain you like from the same dispensary and chances are it will be identical to the same strain you got the last time. But keep in mind: Cannabis is a complicated plant. Cultivators will tell you it seems to have a mind of its own. It can change during cultivation, even transform into a hermaphrodite because of a hidden code in its genes.