A PCR marker linked to a THCA synthase polymorphism is a reliable tool to discriminate potentially THC-rich plants of Cannabis sativa L

J Forensic Sci. 2014 Jul;59(4):919-26. doi: 10.1111/1556-4029.12448. Epub 2014 Mar 3.


Neither absolute THC content nor morphology allows the unequivocal discrimination of fiber cultivars and drug strains of Cannabis sativa L. unequivocally. However, the CBD/THC ratio remains constant throughout the plant's life cycle, is independent of environmental factors, and considered to be controlled by a single locus (B) with two codominant alleles (B(T) and B(D)). The homozygous B(T)/B(T) genotype underlies the THC-predominant phenotype, B(D)/B(D) is CBD predominant, and an intermediate phenotype is induced by the heterozygous state (B(T)/B(D)). Using PCR-based markers in two segregating populations, we proved that the THCA synthase gene represents the postulated B locus and that specific sequence polymorphisms are absolutely linked either to the THC-predominant or the THC-intermediate chemotype. The absolute linkage provides an excellent reliability of the marker signal in forensic casework. For validation, the species-specific marker system was applied to a large number of casework samples and fiber hemp cultivars.

Keywords: Cannabis sativa L.; THCA synthase; chemotype; forensic science; genetic segregation; linkage; molecular marker; species-specific.

MeSH terms

  • Cannabidiol / chemistry
  • Cannabis / chemistry
  • Cannabis / genetics*
  • Dronabinol / chemistry
  • Genetic Linkage
  • Genetic Markers*
  • Intramolecular Oxidoreductases / genetics*
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Polymorphism, Genetic*
  • Sequence Analysis
  • Species Specificity


  • Genetic Markers
  • Cannabidiol
  • Dronabinol
  • Intramolecular Oxidoreductases
  • delta(1)-tetrahydrocannabinolic acid synthase

Associated data

  • GENBANK/JQ935235
  • GENBANK/JQ935236
  • GENBANK/JQ935237
  • GENBANK/JQ935238
  • GENBANK/JQ935239
  • GENBANK/JQ935240
  • GENBANK/JQ935241
  • GENBANK/JQ935242
  • GENBANK/JQ935243
  • GENBANK/JQ935244