We have analyzed the distribution of genotypes at a single hexanucleotide short tandem repeat (STR) locus in a Cannabis sativa seed database along with seed-packaging information. This STR locus is defined by the polymerase chain reaction amplification primers CS1F and CS1R and is referred to as NMI01 (for National Marijuana Initiative) in our study. The population database consists of seed seizures of two categories: seed samples from labeled and unlabeled packages regarding seed bank source. Of a population database of 93 processed seeds including 12 labeled Cannabis varieties, the observed genotypes generated from single seeds exhibited between one and three peaks (potentially six alleles if in homozygous state). The total number of observed genotypes was 54 making this marker highly specific and highly individualizing even among seeds of common lineage. Cluster analysis associated many but not all of the handwritten labeled seed varieties tested to date as well as the National Park seizure to our known reference database containing Mr. Nice Seedbank and Sensi Seeds commercially packaged reference samples.

The validity and feasibility of using DNA collection cards in the field for preservation and analysis of Cannabis sativa genotypes were investigated using a highly specific hexanucleotide marker. Collection cards were submitted to the National Marijuana Initiative, which selectively trained and managed the collection of specific types of samples from a variety of participating agencies. Samples collected at seizure sites included fresh marijuana leaf samples, dried "dispensary" samples, U.S. border seizures, and hashish. Using a standardized PCR kit with custom-labeled oligonucleotide primers specific to marijuana, collection cards produced eight genotypes and 13 different alleles, extremely low baselines, and no cross-reactivity with control plant species. Results were produced from all sample types with the exception of hashish. Plant DNA collection cards represent an easily implementable method for the genetic identification and relatedness of C. sativa street and grow site-seized samples with applications for databasing and market disruption.

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