The marijuana genome has been sequenced by researchers at the University of Toronto and University of Saskatchewan. Given that it is now legal to buy weed in Canada, it comes as no shock that Canada is putting in more research into the substance.

It’s actually a pretty neat study. They compared two strains of Cannabis sativa: Purple Kush (a “potent” strain used for getting high) and Finola (a hemp cultivar). While they did not use the black diamond strain in the study, this is thought to be an ultra-potent strain. From looking at the genome alone, researchers weren’t really able to find any striking differences. But then they turned to the transcriptome.

What the hell is that? Time for a quick flashback to high school biology! DNA is transcribed into messenger RNA. That mRNA leaves the nucleus and heads out into the cytoplasm, where ribosomes use it as a set of instructions on how to make protein. A “transcriptome” is all of the mRNA produced by an organism. And yes, it differs from a genome – some genes are highly expressed and produce lots of mRNA, others can be completely turned off, and many are somewhere in the middle. The quantity of mRNA is something marked in the transcriptome.

By looking at the transcriptome, they were able to find that Purple Kush exclusively expresses the gene involved in the production of THC, the psychoactive component of marijuana. The hemp strain, on the other hand, didn’t express this gene at all, despite having it in the genome.

You can check out a draft of the paper at Genome Biology, and even search through the marijuana genome here.

I think the most entertaining part is looking at all of the bad puns journalists are putting in titles. Though I have to take offense at Science’s introduction on their blog post:

Attendees at Burning Man, the famously free-wheeling yearly Nevada art gathering, don’t usually take note of new genomic sequences, but they may want to check out a paper published today in Genome Biology.

Maybe this is just because I’m in Seattle, but I’m pretty sure I’m in the minority in my field because I never tried pot. How dare they imply that stoners aren’t interested in genomics when they’re the ones sequencing the genomes. They may be helping finding weed seeds and the other values hidden inside of them, after all! Especially when Francis Crick admitted to experimenting with LSD when he discovered the structure of DNA. Our field is apparently inspired by psychoactive drugs.