RT Journal
A1 Laverty, Kaitlin U
A1 Stout, Jake M
A1 Sullivan, Mitchell J
A1 Shah, Hardik
A1 Gill, Navdeep
A1 Holbrook, Larry
A1 Deikus, Gintaras
A1 Sebra, Robert
A1 Hughes, Timothy R
A1 Page, Jonathan E
A1 van Bakel, Harm
T1 A physical and genetic map of Cannabis sativa identifies extensive rearrangement at the THC/CBD acid synthase locus
JF Genome Research 
JO Genome Research 
YR 2018 
FD November 08 
DO 10.1101/gr.242594.118 
SP gr.242594.118 
UL http://genome.cshlp.org/content/early/2018/11/07/gr.242594.118.abstract 
AB Cannabis sativa is widely cultivated for medicinal, food, industrial, and recreational use, but much remains unknown regarding its genetics, including the molecular determinants of cannabinoid content. Here, we describe a combined physical and genetic map derived from a cross between the drug-type strain ‘Purple Kush’ and the hemp variety ‘Finola’. The map reveals that cannabinoid biosynthesis genes are generally unlinked, but that aromatic prenyltransferase (AP), which produces the substrate for THCA and CBDA synthases (THCAS and CBDAS), is tightly linked to a known marker for total cannabinoid content. We further identify the gene encoding CBCA synthase (CBCAS) and characterize its catalytic activity, providing insight into how cannabinoid diversity arises in cannabis. Strikingly, THCAS and CBDAS (which determine the drug vs hemp chemotype) are contained within large (>250 kb) retrotransposon-rich regions that are highly non-homologous between drug- and hemp-type alleles, and are furthermore embedded within ~40 Mb of non-recombining repetitive DNA. The chromosome structures are similar to those in grains such as wheat, with recombination focused in gene-rich, repeat-depleted regions near chromosome ends. The physical and genetic map should facilitate further dissection of genetic and molecular mechanisms in this commercially and medically important plant.