It's Hemp, Not Weed
For some time there’s been a split in the marijuana advocate community. The same split is evidenced in laws and regulations about marijuana. At issue is the difference between hemp and “weed.” Hemp is a version of the marijuana plant used in industry for its strong fibers. It also has potential as a source for both healthy cooking oil and for bio-energy production. Importantly, it does not contain enough THC to make it worth smoking.
Contrast this with marijuana sold for medical or recreational use. Here the level of THC and related compounds is in demand, both on a percentage basis (stronger = better) and for the mix of chemicals that shapes the high. The question that has recently been answered by genomic analysis is just what makes the two forms of the plant so different.
In a report out of Genome Biology (available as a preprint), geneticists have determined that a single gene is blocked in the hemp version, but not in the other. It also points out how long ago selective breeding changed the plant from a fiber producing wonder into a recreational drug.
The gene involved switches on an enzyme (in hemp) that removes a precursor of THC in the biological pathway. Furthermore another gene is switched on in the plants that produce THC which isn’t in the hemp version.
The two varieties compared were Purple Kush and Finola (a plant grown for fibers). The interesting thing is that the genetic variation gives some additional ammunition for those who wish to allow full rights for hemp cultivation without restriction – after all, there is clearly a genetic difference. This demonstrates you can’t simply change hemp to a smokable form, something advocates have known for a long time.
This new discovery also opens up the possibility of direct genetic manipulation of the plant to either increase the amount of THC produced or block it entirely.