Editing Cannabis (section)

===Sex determination===
{{See also|Cytogenetics#History}}
''Cannabis'' has been described as having one of the most complicated mechanisms of [[Sex-determination system|sex determination]] among the dioecious plants.<ref name="truta2002a"/> Many models have been proposed to explain sex determination in ''Cannabis''.

Based on studies of sex reversal in [[hemp]], it was first reported by K. Hirata in 1924 that an [[XY sex-determination system]] is present.<ref name="hirata1924"/> At the time, the XY system was the only known system of sex determination. The [[X0 sex-determination system|X:A system]] was first described in ''[[Drosophila]]'' spp in 1925.<ref name="bridges1925">{{cite journal| vauthors = Bridges CB |year= 1925 |title=Sex in Relation to Chromosomes and Genes|journal=The American Naturalist|volume=59|issue=661|pages=127–37|jstor=2456354|doi=10.1086/280023|bibcode= 1925ANat...59..127B |s2cid=84528876}}</ref> Soon thereafter, Schaffner disputed Hirata's interpretation,<ref name="schaffner1929">{{cite journal|hdl=1811/2398| vauthors = Schaffner JH |year=1929|title=Heredity and sex|journal=Ohio Journal of Science|volume=29|issue=1|pages=289–300}}</ref> and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that furthermore sex was strongly influenced by environmental conditions.<ref name="schaffner1931"/>

Since then, many different types of sex determination systems have been discovered, particularly in plants.<ref name="ainsworth2000"/> Dioecy is relatively uncommon in the plant kingdom, and a very low percentage of dioecious plant species have been determined to use the XY system. In most cases where the XY system is found it is believed to have evolved recently and independently.<ref name="negrutiu2001">{{cite journal | vauthors = Negrutiu I, Vyskot B, Barbacar N, Georgiev S, Moneger F | title = Dioecious plants. A key to the early events of sex chromosome evolution | journal = Plant Physiology | volume = 127 | issue = 4 | pages = 1418–24 | date = December 2001 | pmid = 11743084 | pmc = 1540173 | doi = 10.1104/pp.010711 }}</ref>

Since the 1920s, a number of sex determination models have been proposed for ''Cannabis''. Ainsworth describes sex determination in the genus as using "an X/autosome dosage type".<ref name="ainsworth2000"/>

The question of whether heteromorphic [[sex chromosomes]] are indeed present is most conveniently answered if such chromosomes were clearly visible in a [[karyotype]]. ''Cannabis'' was one of the first plant species to be karyotyped; however, this was in a period when karyotype preparation was primitive by modern standards. Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious "Kentucky" hemp, but were not found in pistillate individuals of the same variety. Dioecious "Kentucky" hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious "Kentucky" hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX.<ref name="menzel1964">{{cite journal| vauthors = Menzel MY |year=1964|title=Meiotic Chromosomes of Monoecious Kentucky Hemp (Cannabis sativa)|journal=Bulletin of the Torrey Botanical Club|volume=91|issue=3|pages=193–205|jstor=2483524|doi=10.2307/2483524}}</ref> According to other researchers, no modern karyotype of ''Cannabis'' had been published as of 1996.<ref name="hong1996a">{{cite journal |vauthors=Hong S, Clarke RC |year=1996 |url=http://www.hempfood.com/IHA/iha03207.html |title=Taxonomic studies of Cannabis in China |journal=Journal of the International Hemp Association |volume=3 |issue=2 |pages=55–60 |access-date=7 September 2006 |archive-date=9 August 2012 |archive-url=https://web.archive.org/web/20120809052050/http://www.hempfood.com/iha/iha03207.html |url-status=live }}</ref> Proponents of the XY system state that [[Y&nbsp;chromosome]] is slightly larger than the X, but difficult to differentiate cytologically.<ref name="peil2003">{{cite journal | vauthors = Peil A, Flachowsky H, Schumann E, Weber WE | title = Sex-linked AFLP markers indicate a pseudoautosomal region in hemp ( Cannabis sativa L.) | journal = Theoretical and Applied Genetics | volume = 107 | issue = 1 | pages = 102–9 | date = June 2003 | pmid = 12835935 | doi = 10.1007/s00122-003-1212-5 | s2cid = 11453369 }}</ref>

More recently, Sakamoto and various co-authors<ref name="sakamoto1995a">{{cite journal | vauthors = Sakamoto K, Shimomura K, Komeda Y, Kamada H, Satoh S | title = A male-associated DNA sequence in a dioecious plant, Cannabis sativa L | journal = Plant & Cell Physiology | volume = 36 | issue = 8 | pages = 1549–54 | date = December 1995 | pmid = 8589931 }}</ref><ref name="sakamoto2005a">{{cite journal | vauthors = Sakamoto K, Abe T, Matsuyama T, Yoshida S, Ohmido N, Fukui K, Satoh S | s2cid = 40436657 | title = RAPD markers encoding retrotransposable elements are linked to the male sex in Cannabis sativa L | journal = Genome | volume = 48 | issue = 5 | pages = 931–6 | date = October 2005 | pmid = 16391699 | doi = 10.1139/g05-056 }}</ref> have used [[random amplification of polymorphic DNA]] (RAPD) to isolate several [[genetic marker]] sequences that they name Male-Associated DNA in ''Cannabis'' (MADC), and which they interpret as indirect evidence of a male chromosome. Several other research groups have reported identification of male-associated markers using RAPD and [[amplified fragment length polymorphism]].<ref name="meijer2003a" /><ref name="mandolino2002a" /><ref name="torjek2002">{{cite journal |doi=10.1023/A:1020204729122 |year=2002 | vauthors = Törjék O, Bucherna N, Kiss E, Homoki H, Finta-Korpelová Z, Bócsa I, Nagy I, Heszky LE |journal=Euphytica |volume=127 |issue=2 |pages=209–218|title=Novel male-specific molecular markers (MADC5, MADC6) in hemp|s2cid=27065456 }}</ref> Ainsworth commented on these findings, stating,

{{Blockquote|It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination.<ref name="ainsworth2000" />}}

Environmental sex determination is known to occur in a variety of species.<ref name="tanurdzic2004">{{cite journal | vauthors = Tanurdzic M, Banks JA | title = Sex-determining mechanisms in land plants | journal = The Plant Cell | volume = 16 | issue = Suppl | pages = S61-71 | year = 2004 | pmid = 15084718 | pmc = 2643385 | doi = 10.1105/tpc.016667 | bibcode = 2004PlanC..16S..61T }}</ref> Many researchers have suggested that sex in ''Cannabis'' is determined or strongly influenced by environmental factors.<ref name=schaffner1931/> Ainsworth reviews that treatment with [[auxin]] and [[Ethylene as a plant hormone|ethylene]] have feminizing effects, and that treatment with [[cytokinins]] and [[gibberellins]] have masculinizing effects.<ref name=ainsworth2000/> It has been reported that sex can be reversed in ''Cannabis'' using chemical treatment.<ref name="mohanram1982">{{cite journal | vauthors = Mohan Ram HY, Sett R | title = Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulphate anionic complex | journal = Theoretical and Applied Genetics | volume = 62 | issue = 4 | pages = 369–75 | date = December 1982 | pmid = 24270659 | doi = 10.1007/BF00275107 | s2cid = 12256760 }}</ref> A [[polymerase chain reaction]]-based method for the detection of female-associated [[Polymorphism (biology)|DNA polymorphisms]] by [[genotyping]] has been developed.<ref name=PCR>{{cite journal |doi=10.1300/J237v08n01_02 |title=Female-Associated DNA Polymorphisms of Hemp (Cannabis sativaL.) |year=2003| vauthors = Shao H, Song SJ, Clarke RC |journal=Journal of Industrial Hemp |volume=8 |issue=1 |pages=5–9 |s2cid=84460585 }}</ref>

<gallery widths="180px" heights="200px">
File:Hemp plants-cannabis sativa-single 3.JPG|A male hemp plant
File:Cannabis indica Selkem.jpg|Dense raceme of female flowers typical of drug-type varieties of ''Cannabis''
File:Male Cannabis Lemon Kush (Entire Plant).jpg|Male Lemon Kush cannabis plant (12 foot plant)
File:Male Lemon Kush Cannabis Plant.jpg|Male Lemon Kush cannabis Flowers
File:Alcapulco Gold Young Plant.jpg|A young female [[Acapulco Gold]] plant (Mexican x Nepalese). Seed grown plant from seeds obtained from a cannabis seed bank.<ref name="r501">{{cite web | last=M. | first=Linda | title=Buy Acapulco Gold Feminized Seeds | website=Seed Supreme | date=2024-08-03 | url=https://seedsupreme.com/acapulco-gold-feminized.html | access-date=2024-08-07}}</ref>
File:Acapulco Gold Female Plant in Bloom 1.jpg|Acapulco Gold female plant in bloom
File:Indoor grown Acapulco Gold in Final Stages of Flowering 1.jpg|Indoor grown Acapulco Gold female plant in final stages of flowering (flushing in amber and gold tones)
</gallery>