October 20, 2011
Researchers Sequence Cannabis Genome
Researchers have sequenced DNA from the marijuana strain Purple Kush (PK) for the first time, unveiling the genome of how these plants evolved.
The PK genome and transcriptome were compared to those of "Finola" hemp, and scanned for differences that might help explain why marijuana produces tetrahydrocannabinolic acid (THCA), while hemp does not.Hemp seed oil is rich in omega 6, which is an essential fatty acid, and its fiber is used in the production of fabrics. Hemp does not have the same effects as marijuana because it does not contain the intoxicating chemical THCA. However, hemp does contain the non-psychoactive cannabinoid, cannabidiolic acid (CBDA).
Dr John Page, who helped with the research, said the transcriptome held the clues to solving this genome puzzle of why marijuana contained THCA and hemp did not.
"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 said in a press release.
Dr Tim Hughes, another researcher involved in the project, said cultivation could have played the role to marijuana losings CBDA.
"Detailed analysis of the two genomes suggests that domestication, cultivation, and breeding of marijuana strains has caused the loss of the enzyme (CBDA synthase) which would otherwise compete for the metabolites used as starting material in THCA production," Hughes said in a press release.
Page said this is the first genome of a medicinal plant, despite the 20 other plant genomes that have been published.
"Decoding the cannabis genome will help answer basic questions about the biology of Cannabis sativa and further the development of its myriad applications including strains for pharmaceutical production, and hemp plants with improved productivity and fatty acid profiles," Page said in a press release.
The study was published in BioMed Central's open access journal Genome Biology.
Image Caption: A bud of Purple Kush. Credit: Wikipedia
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