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Gene copy number is associated with phytochemistry in Cannabis sativa

Cannabinoid compounds are one of the defining properties of the angiosperm Cannabis sativa (wild marijuana). Many of these compounds have potential medicinal applications, for example in the treatment of pain, particularly for those with terminal or chronic illnesses. Recently, humans have bred intensively for high levels of THCA (delta-9-tetrahydrocannabinolic acid) and CBDA (cannabidiolic acid), the two most abundant and well-studied secondary metabolites produced by the plant. Variation in cannabinoid concentrations has been observed across varieties of C. sativa yet the underlying genetic control of this diversity is poorly understood.

Botanical painting of Cannabis sativa on hemp paper. Image credit: © 2017 Linda M. Powers (for more details of Linda’s work please visit her website

THCA and CBDA were thought to have a simple mode of inheritance; however, a recent study by Vergara et al. describes that in fact multiple gene copies are involved in their production. Their results, published in AoBP, show that varieties and individuals differ in the number of gene copies. They also show that the number of copies may be related to the amount of cannabinoid production. They also found the expression of these genes to vary within varieties. An interesting remaining unknown from this study is the possession of multiple other genes with unknown phytochemical products, which could also have medicinal importance. The authors state that their work will hopefully open the door to future research on these unknown compounds as well as further study on THCA and CBDA production.

Researcher highlight

Dr. Daniela Vergara is an evolutionary biologist researching Cannabis genomics at the University of Colorado Boulder, USA. In addition to her multiple publications in Cannabis, she founded and directs a non-profit organization, the Agricultural Genomics Foundation (AGF; AGF’s aim is to make Cannabis science available to a broad public. Vergara is also part of the scientific company Steep Hill, Inc. who are a global leader in Cannabis science and lab testing.

To find out more about Daniela and her research please visit her website at

Written by William Salter

William (Tam) Salter is a Postdoctoral Research Associate in the School of Life and Environmental Sciences and Sydney Institute of Agriculture at the University of Sydney. He has a bachelor degree in Ecological Science (Hons) from the University of Edinburgh and a PhD in plant ecophysiology from the University of Sydney. Tam is interested in the identification and elucidation of plant traits that could be useful for ecosystem resilience and future food security under global environmental change. He also has an active interest in effective scientific communication.

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