Gap-Free Cannabis sativa Assemblies Reveal Post-Polyploid Genome Remodelling and Refine the Evolution of Cannabinoid Synthase Genes.

Zhang J.; Qin C.; Li Z.; Zhao L.; Biswas A.; Liu T.; Luan M.; Li L.; Li D.; Yan J. · Plant biotechnology journal · 2026

**Background & Methods** This genomic research study generated two haplotype-phased, gap-free genome assemblies of Cannabis sativa to investigate post-polyploid genome remodelling and trace the evolutionary history of cannabinoid synthase genes. The researchers conducted comparative phylogenomic, structural, and syntenic analyses to reconstruct the evolutionary origins and diversification of cannabinoid biosynthesis pathways. **Key Findings** • Gap-free Cannabis assemblies identified a γ whole-genome triplication (WGT) signal shared with core eudicots, with no evidence of additional lineage-specific whole-genome duplications (WGD) in Cannabis. The modern Cannabis genome reflects selective retention and divergence of γ-derived duplicates combined with non-WGD gene duplications and repeat-associated remodelling contributing to contemporary genome diversity. • A precursor duplication event preceding the Cannabis-Humulus evolutionary split generated two ancestral lineages retained on Cannabis chromosomes 7 and 2. The chromosome 7 lineage underwent subsequent expansion and functional diversification into contemporary cannabinoid synthase genes, while the related genus Humulus retained only the chromosome 2-type lineage. • This asymmetric retention and diversification pattern provides mechanistic insight into the origin, specialization, and functional divergence of cannabinoid biosynthesis unique to Cannabis species, distinguishing it from related plant genera. **Dosage & Administration** Not reported. **Safety & Adverse Effects** Not reported. **Evidence Quality** This is a genomic and evolutionary biology study rather than a clinical investigation, representing high-quality foundational research based on gap-free reference genome assemblies (gold-standard quality). Limitations include focus on genomic architecture without direct functional validation of all identified cannabinoid synthase variants. The study provides a robust framework for future investigations but does not include experimental data on cannabinoid production levels, bioactivity, or clinical efficacy. As a basic science contribution published in a peer-reviewed botanical biotechnology journal, it establishes critical genomic infrastructure for subsequent translational cannabinoid research but should not be interpreted as direct evidence for clinical applications.

More recent cannabis research