Identification of illegal substances is of great concern to law enforcement personnel. Cannabis sativa, or marijuana, is frequently encountered in criminal investigations. Current methods for identification of marijuana include microscopic examination for characteristic morphological features, chemical tests (e.g., Duquenois or Duquenois-Levine test), and cannabinoid compound identification by gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), or thin layer chromatography (TLC). A number of molecular genetic tests have been developed that also permit the identification of marijuana.^59-64 These include DNA sequence analysis of the internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal DNA and the intergenic spacer region of chloroplast DNA (trn L-trnF IGS).

Once a substance has been identified as marijuana, it may be possible to individualize that sample to determine the originating source using DNA techniques: randomly amplified polymorphic DNA markers (RAPDs), amplified fragment length polymorphisms (AFLPs), and short tandem repeats (STRs). Such studies may facilitate the prosecution of major growers and distributors. Marijuana databases are being constructed in order to provide aid in determining  the significance of a match between profiles from evidence samples.⁶⁴

Back Forward