Strains of cannabis sativa and cannabis indica possess relatively few significant genetic differences and are often mislabeled by breeders, according to an evaluation of marijuana taxonomy published online last week in the journal PLOS ONE.
Investigators from the University of Manitoba, the University of British Columbia, and Dalhousie University in Nova Scotia evaluated the genetic structure of a diverse range of commonly cultivated marijuana and industrial hemp samples.
Researchers reported, “We find a moderate correlation between the genetic structure of marijuana strains and their reported C. sativa and C. indica ancestry and show that marijuana strain names often do not reflect a meaningful genetic identity.” They added, “This observation suggests that C. sativa and C. indica may represent distinguishable pools of genetic diversity, but that breeding has resulted in considerable admixture between the two. … Our results suggest that the reported ancestry of some of the most common marijuana strains only partially captures their true ancestry.”
By contrast, authors determined, “[M]arijuana and hemp are significantly differentiated at a genome-wide level, demonstrating that the distinction between these populations is not limited to genes underlying THC production. … [This] difference between marijuana and hemp plants has considerable legal implications in many countries.”
In the United States, federal law makes no legal distinction between hemp and cannabis.
Authors concluded: “Achieving a practical, accurate and reliable classification system for cannabis, including a variety registration system for marijuana-type plants, will require significant scientific investment and a legal framework that accepts both licit and illicit forms of this plant. Such a system is essential in order to realize the enormous potential of Cannabis as a multi-use crop (hemp) and as a medicinal plant (marijuana).”
Full text of the study, “The genetic structure of marijuana and hemp,” appears online here.