Cannabis Genome Mapped

O Canada, we stand on guard for thee.
God keep our Weed glorious and free!
O Canada, we stand on guard for thee.

Jon Page is a plant biochemist and adjunct professor of biology at the University of Saskatchewan. He explains that a simple genetic switch is likely responsible for the production of THCA, or tetrahydrocannabinolic acid, the precursor of the active ingredient in marijuana.

"The transcriptome analysis showed that the THCA synthase gene, an essential enzyme in THCA production, is turned on in marijuana, but switched off in hemp," Page says.

(...) over thousands of years of cultivation, hemp farmers selectively bred Cannabis sativa into two distinct strains -- one for fibre and seed, and one for medicine. Marijuana has been used medicinally for more than 2,700 years, and continues to be explored for its pharmaceutical potential.

How Hemp Got High: Cannabis Genome Mapped @ Science Daily