Genetic Cannabinoid Screening

Plant genetics can be coached to express varying concentrations of cannabinoids, but the relative ratios of the key cannabinoids, THCA and CBDA, are usually genetically determined. As an example, there are no known agricultural methods to make a CBDA-dominant strain become a THCA-dominant strain via environmental conditions. These critical chemotypes are governed by gene knockouts in their respective enzymatic synthases (CBDA Synthase and THCA Synthase).

Use Genetic Screening to Determine Plant Type

Most cannabis plants can be classified into four groups based on their cannabinoids profiles: THCA-dominant Type I plants, THCA:CBDA hybrid Type II plants, CBDA dominant Type III plants, and CBG-dominant Type IV plants. Cultivators can use genetic screening tools that detect whether the THCA synthase gene and/or the CBDA synthase gene is present in a plant. Different combinations of results on the respective tests will indicate the plant type.


Type I Plant


Type II Plant


Type III Plant


Type IV Plant


*Plants that test negative for THCA or CBDA may still produce low percentages (<2%) of either compound.

Powered by youPCR®

youPCR Results photoMedicinal Genomics offers THCA synthase and CBDA synthase detection tests that run on the youPCR® Plant Screening Platform. Plant DNA is obtained from a small hole punch in the leaf. If the DNA sample contains the target sequence, a chemical reaction will turn the pink solution yellow, indicating a positive result.


Learn More about youPCR

Available Cannabinoid Screening Products

420212youPCR® Solution B – CBDA50Buy Now
420214youPCR® CBDA Positive Control50Buy Now
420217youPCR® Solution B – THCA50Buy Now
420218youPCR® THCA Positive Control50Buy Now

Getting Started

Getting started with the youPCR is as easy as 1, 2, 3.

Purchase chemical reagents from Medicinal Genomics webstore.

Purchase equipment and consumables. Starter Bundles available in our webstore!


Frequently Asked Questions

No. Although we have done some initial research into using youPCR® to test seeds, we have not done enough to confidently say it works as well as testing leaf. We recommend sampling a seedling’s first set of true leaves when using youPCR®.

youPCR® assays provide a positive/negative result. When using youPCR® to screen for CBDA or THCA synthase, a positive result means there is an active CBDA or THCA synthase allele. Unfortunately, that result can’t be used to predict what percentage the plant will ultimately produce. However, if you combine the CBDA and THCA tests you can determine the plant type.

  • Type I Plant (THCA-dominant) = THCA(+) CBDA(-)
  • Type II Plant (THCA:CBDA hybrid) = THCA(+) CBDA (+)
  • Type III Plant (CBDA-dominant) = THCA(-) CBDA(+)
  • Type IV Plant (CBGA-dominant) = THCA(-) CBDA(-)

No. Plants that test negative for THCA or CBDA may still produce low percentages (<2%) of either compound.

No. Cannabis plants typically hermie as a response to stress. Although there may be genetic markers that determine if a plant is more likely to hermie, we have not found them, and we do not target them with our gender test. The youPCR® Gender Assay specifically looks for a Y chromosome.

The youPCR® Starter Kits do not include PCR Thermal Cyclers. We recommend the following models:

  • miniPCR. Use Promo Code “MGC” to receive a discount off list price.

The youPCR® Starter Kits also do not include chemical reagents: Solution A, Solution B, Solution C, and Positive Control. Those must be purchased separately on the Medicinal Genomics web store.

In order to successfully test with youPCR®, you should have experience with the following laboratory techniques/best practices:

  • Liquid handling with a pipette
  • Benchtop sterility techniques
  • Proper disposal of tips, punches, strip tubes

All of the chemicals and reagents we sell in our webstore are manufactured in facilities that are certified to ISO 9001 and/or ISO 13485 standards.

Still have questions? Don’t hesitate to reach out to us.

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