A team led by investigators at the University of Toronto reports in a paper published online in advance in Genome Biology this week, a draft genome and transcriptome of the Purple Kush strain of a plant they say "occupies a unique role in human culture," Cannabis sativa. The Toronto-led team reports having sequenced genomic DNA and RNA from the marijuana strain using short-read approaches. Further, the team compared the Purple Kush transcriptome with that of the hemp cultivar Finola. Additionally, "single-nucleotide variant analysis uncovered a relatively high level of variation between cannabis types, and supported a separation of marijuana and hemp," the authors write. The University of Saskatchewan's Jonathan Page, a co-author on the paper, tells Daily Scan's sister publication GenomeWeb Daily News that "biochemically and chemically, people had known that there's this bifurcation in the pathway in marijuana and hemp, but this was the first molecular evidence for what was occurring." Of the Purple Kush transcriptome, Page adds, "We think this is sort of a molecular signature of the selection by humans over time of high-THC strains. … We think this probably represents transcriptional control, where one or more transcription factors that control that pathway are turned on and then up-regulate those genes."
The Purple Kush Genome
Oct 20, 2011