A completeCannabischromosome assembly and adaptive admixture for elevated cannabidiol (CBD) content

Abstract

Cannabis has been cultivated for millennia with distinct cultivars providing either fiber and grain or tetrahydrocannabinol. Recent demand for cannabidiol rather than 20 tetrahydrocannabinol has favored the breeding of admixed cultivars with extremely high cannabidiol content. Despite several draft Cannabis genomes, the genomic structure of cannabinoid synthase loci has remained elusive. A genetic map derived from a tetrahydrocannabinol/cannabidiol segregating population and a complete chromosome assembly from a high-cannabidiol cultivar together resolve the linkage 25 of cannabidiolic and tetrahydrocannabinolic acid synthase gene clusters which are associated with transposable elements. High-cannabidiol cultivars appear to have been generated by integrating hemp-type cannabidiolic acid synthase gene clusters into a background of marijuana-type cannabis. Quantitative trait locus mapping suggests that overall drug potency, however, is associated with other genomic regions needing 30 additional study. Resources available online at: http://cannabisgenome.org SummaryA complete chromosome assembly and an ultra-high-density linkage map together identify the genetic mechanism responsible for the ratio of tetrahydrocannabinol 35 (THC) to cannabidiol (CBD) in Cannabis cultivars, allowing paradigms for the evolution and inheritance of drug potency to be evaluated. 45 has also frustrated attempts to assemble complete chromosomes from thousands of Veronica Tonnell contributed DNA isolation for the mapping population. We thank

Development and validation of genetic markers for sex and cannabinoid chemotype in Cannabis sativa L.

“…Since the CCP-1 assay examines CBDAS only and CBDAS and THCAS are not allelic, it is possible that a plant with a recombination between CBDAS and THCAS would not be scored correctly. However, we did not detect this in any of our samples, and the tight linkage in repulsion between CBDAS and THCAS is well established Grassa et al, 2018;Weiblen et al, 2015). The mean Δ 9 -THC and total potential THC concentrations as percent dry matter were significantly different in each chemotype.…”

“…The genetic structure of CBDAS and THCAS have been recently elucidated (Grassa et al, 2018;Laverty et al, 2019). While the genes are highly alike, sharing 84% amino acid identity (Onofri, de Meijer, & Mandolino, 2015), they are not allelic or at equivalent loci.…”

Genome‐wide analysis of MIKC‐type MADS‐box genes in wheat: pervasive duplications, functional conservation and putative neofunctionalization

“…The genome architecture among different plants varies considerably. Arabidopsis and rice, for example, have relatively small subtelomeric regions (The Arabidopsis Genome Initative, ; Mizuno et al ., ), whereas other plants show increased recombination rates towards the chromosome ends and relatively large distal telomeric regions with increased gene content, very similar to what is seen in wheat (Choulet et al ., ; Glover et al ., ; Li et al ., ; Lambing et al ., ; Grassa et al ., ; Sun et al ., ; Laverty et al ., ). It will be interesting to see whether similar dynamics of MIKC‐type MADS‐box gene duplications can be observed in those species.…”

The Cannabis Multi-Omics Draft Map Project

“…Despite these challenges we have built considerably on the existing knowledge of the Cannabis proteome and have generated a relatively complete picture of the protein composition of the plants we have analyzed to date. Genomic analysis has identified approximately 25,000 protein coding regions, a number comparable to that of humans in a Cannabis chromosome assembly 33 . While exact numbers are still currently debated, no study to our knowledge as identified more 20,000 or more unique protein groups in humans.…”

“…All samples were obtained by Think20Labs under the guidelines of the MMCC regulations in accordance with a temporary license granted under COMAR 10.62. 33. 13 A recent study described the optimization of digestion conditions for the proteomic analysis of Cannabis flowers and performed similar experiments as the ones described here.…”