with cytokinins and gibberellins have masculinizing effects. It has been reported that sex can be reversed in Cannabis using chemical treatment. A polymerase chain reaction-based method for the detection of female-associated DNA polymorphisms by genotyping has been developed. Chemistry Cannabis plants produce a large number of chemicals as part of their defense against herbivory. One group of these is called cannabinoids, which induce mental and physical effects when consumed. Cannabinoids, terpenoids, and other compounds are secreted by glandular trichomes that occur most abundantly on the floral calyxes and bracts of female plants. Genetics Cannabis, like many organisms, is diploid, having a chromosome complement of 2n=20, although polyploid individuals have been artificially produced. The first genome sequence of Cannabis, which is estimated to be 820 Mb in size, was published in 2011 by a team of Canadian scientists. Taxonomy The genus Cannabis was formerly placed in the nettle family (Urticaceae) or mulberry family (Moraceae), and later, along with the genus Humulus (hops), in a separate family, the hemp family (Cannabaceae sensu stricto). Recent phylogenetic studies based on cpDNA restriction site analysis and gene sequencing strongly suggest that the Cannabaceae sensu stricto arose from within the former family Celtidaceae, and that the two families should be merged to form a single monophyletic family, the Cannabaceae sensu lato. Various types of Cannabis have been described, and variously classified as species, subspecies, or varieties: plants cultivated for fiber and seed production, described as low-intoxicant, non-drug, or fiber types. plants cultivated for drug production, described as high-intoxicant or drug types. escaped, hybridised, or wild forms of either of the above types. Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, some of which produce the "high" which may be experienced from consuming marijuana. There are 483 identifiable chemical constituents known to exist in the cannabis plant, and at least 85 different cannabinoids have been isolated from the plant. The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ9-tetrahydrocannabinol (THC), but only THC is psychoactive. Since the early 1970s, Cannabis plants have been categorized by their chemical phenotype or "chemotype", based on the overall amount of THC produced, and on the ratio of THC to CBD. Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant. Non-drug plants produce relatively low levels of THC and high levels