Editing Polyploidy (section)

=== Plants ===
[[File:Polyploidization.svg|right|thumb|[[Speciation]] via polyploidy: A [[diploid]] cell undergoes failed [[meiosis]], producing diploid [[gamete]]s, which self-fertilize to produce a tetraploid [[zygote]].]]

Polyploidy is frequent in plants, some estimates suggesting that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy ([[paleopolyploidy]]) in their genomes.<ref name="pmid16892970">{{cite journal | vauthors = Meyers LA, Levin DA | title = On the abundance of polyploids in flowering plants | journal = Evolution; International Journal of Organic Evolution | volume = 60 | issue = 6 | pages = 1198–1206 | date = June 2006 | pmid = 16892970 | doi = 10.1111/j.0014-3820.2006.tb01198.x | doi-access = free }}</ref><ref name="Rieseberg_2007">{{cite journal | vauthors = Rieseberg LH, Willis JH | title = Plant speciation | journal = Science | volume = 317 | issue = 5840 | pages = 910–914 | date = August 2007 | pmid = 17702935 | pmc = 2442920 | doi = 10.1126/science.1137729 | bibcode = 2007Sci...317..910R }}</ref><ref name="pmid17981114">{{cite journal | vauthors = Otto SP | title = The evolutionary consequences of polyploidy | journal = Cell | volume = 131 | issue = 3 | pages = 452–462 | date = November 2007 | pmid = 17981114 | doi = 10.1016/j.cell.2007.10.022 | doi-access = free }}</ref><ref>{{cite journal | title = One thousand plant transcriptomes and the phylogenomics of green plants | journal = Nature | volume = 574 | issue = 7780 | pages = 679–685 | date = October 2019 | pmid = 31645766 | pmc = 6872490 | doi = 10.1038/s41586-019-1693-2 | author1 = One Thousand Plant Transcriptomes Initiative }}</ref> Huge explosions in [[angiosperm]] species diversity appear to have coincided with the timing of ancient genome duplications shared by many species.<ref>{{cite journal | vauthors = De Bodt S, Maere S, Van de Peer Y | title = Genome duplication and the origin of angiosperms | journal = Trends in Ecology & Evolution | volume = 20 | issue = 11 | pages = 591–597 | date = November 2005 | pmid = 16701441 | doi = 10.1016/j.tree.2005.07.008 }}</ref> It has been established that 15% of angiosperm and 31% of fern [[speciation]] events are accompanied by ploidy increase.<ref name="pmid19667210">{{cite journal | vauthors = Wood TE, Takebayashi N, Barker MS, Mayrose I, Greenspoon PB, Rieseberg LH | title = The frequency of polyploid speciation in vascular plants | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 106 | issue = 33 | pages = 13875–13879 | date = August 2009 | pmid = 19667210 | pmc = 2728988 | doi = 10.1073/pnas.0811575106 | doi-access = free | bibcode = 2009PNAS..10613875W | jstor = 40484335 }}</ref>

Polyploid plants can arise spontaneously in nature by several mechanisms, including meiotic or mitotic failures, and fusion of unreduced (2''n'') gametes.<ref name="Comai_2005"/> Both autopolyploids (e.g. potato<ref name="Consortium The Potato Genome Sequencing 2011 189–195">{{cite journal | vauthors = Xu X, Pan S, Cheng S, Zhang B, Mu D, Ni P, Zhang G, Yang S, Li R, Wang J, Orjeda G, Guzman F, Torres M, Lozano R, Ponce O, Martinez D, De la Cruz G, Chakrabarti SK, Patil VU, Skryabin KG, Kuznetsov BB, Ravin NV, Kolganova TV, Beletsky AV, Mardanov AV, Di Genova A, Bolser DM, Martin DM, Li G, Yang Y, Kuang H, Hu Q, Xiong X, Bishop GJ, Sagredo B, Mejía N, Zagorski W, Gromadka R, Gawor J, Szczesny P, Huang S, Zhang Z, Liang C, He J, Li Y, He Y, Xu J, Zhang Y, Xie B, Du Y, Qu D, Bonierbale M, Ghislain M, Herrera M, Giuliano G, Pietrella M, Perrotta G, Facella P, O'Brien K, Feingold SE, Barreiro LE, Massa GA, Diambra L, Whitty BR, Vaillancourt B, Lin H, Massa AN, Geoffroy M, Lundback S, DellaPenna D, Buell CR, Sharma SK, Marshall DF, Waugh R, Bryan GJ, Destefanis M, Nagy I, Milbourne D, Thomson SJ, Fiers M, Jacobs JM, Nielsen KL, Sønderkær M, Iovene M, Torres GA, Jiang J, Veilleux RE, Bachem CW, de Boer J, Borm T, Kloosterman B, van Eck H, Datema E, Hekkert B, Goverse A, van Ham RC, Visser RG | display-authors = 6 | title = Genome sequence and analysis of the tuber crop potato | journal = Nature | volume = 475 | issue = 7355 | pages = 189–195 | date = July 2011 | pmid = 21743474 | doi = 10.1038/nature10158 | doi-access = free }}</ref>) and allopolyploids (such as canola, wheat and cotton) can be found among both wild and domesticated plant species.

Most polyploids display novel variation or morphologies relative to their parental species, that may contribute to the processes of [[speciation]] and eco-niche exploitation.<ref name="Rieseberg_2007" /><ref name="Comai_2005" /> The mechanisms leading to novel variation in newly formed allopolyploids may include gene dosage effects (resulting from more numerous copies of genome content), the reunion of divergent gene regulatory hierarchies, chromosomal rearrangements, and [[epigenetic]] remodeling, all of which affect gene content and/or expression levels.<ref name="pmid12615008">{{cite journal | vauthors = Osborn TC, Pires JC, Birchler JA, Auger DL, Chen ZJ, Lee HS, Comai L, Madlung A, Doerge RW, Colot V, Martienssen RA | display-authors = 6 | title = Understanding mechanisms of novel gene expression in polyploids | journal = Trends in Genetics | volume = 19 | issue = 3 | pages = 141–147 | date = March 2003 | pmid = 12615008 | doi = 10.1016/S0168-9525(03)00015-5 }}</ref><ref name="pmid16479580">{{cite journal | vauthors = Chen ZJ, Ni Z | title = Mechanisms of genomic rearrangements and gene expression changes in plant polyploids | journal = BioEssays | volume = 28 | issue = 3 | pages = 240–252 | date = March 2006 | pmid = 16479580 | pmc = 1986666 | doi = 10.1002/bies.20374 }}</ref><ref name="pmid17280525">{{cite journal | vauthors = Chen ZJ | title = Genetic and epigenetic mechanisms for gene expression and phenotypic variation in plant polyploids | journal = Annual Review of Plant Biology | volume = 58 | pages = 377–406 | year = 2007 | pmid = 17280525 | pmc = 1949485 | doi = 10.1146/annurev.arplant.58.032806.103835 }}</ref><ref>{{cite journal | vauthors = Albertin W, Balliau T, Brabant P, Chèvre AM, Eber F, Malosse C, Thiellement H | title = Numerous and rapid nonstochastic modifications of gene products in newly synthesized Brassica napus allotetraploids | journal = Genetics | volume = 173 | issue = 2 | pages = 1101–1113 | date = June 2006 | pmid = 16624896 | pmc = 1526534 | doi = 10.1534/genetics.106.057554 }}</ref> Many of these rapid changes may contribute to reproductive isolation and speciation. However, seed generated from [[interploidy hybridization|interploidy crosses]], such as between polyploids and their parent species, usually have aberrant endosperm development which impairs their viability,<ref>{{cite journal | vauthors = Pennington PD, Costa LM, Gutierrez-Marcos JF, Greenland AJ, Dickinson HG | title = When genomes collide: aberrant seed development following maize interploidy crosses | journal = Annals of Botany | volume = 101 | issue = 6 | pages = 833–843 | date = April 2008 | pmid = 18276791 | pmc = 2710208 | doi = 10.1093/aob/mcn017 }}</ref><ref>{{cite journal | vauthors = von Wangenheim KH, Peterson HP | title = Aberrant endosperm development in interploidy crosses reveals a timer of differentiation | journal = Developmental Biology | volume = 270 | issue = 2 | pages = 277–289 | date = June 2004 | pmid = 15183714 | doi = 10.1016/j.ydbio.2004.03.014 | doi-access =  }}</ref> thus contributing to [[polyploid speciation]]. Polyploids may also interbreed with diploids and produce polyploid seeds, as observed in the agamic complexes of ''[[Crepis]]''.<ref>{{cite journal | vauthors = Whitton J, Sears CJ, Maddison WP | title = Co-occurrence of related asexual, but not sexual, lineages suggests that reproductive interference limits coexistence | journal = Proceedings. Biological Sciences | volume = 284 | issue = 1868 | pages = 20171579 | date = December 2017 | pmid = 29212720 | pmc = 5740271 | doi = 10.1098/rspb.2017.1579 }}</ref>

Some plants are triploid. As [[meiosis]] is disturbed, these plants are sterile, with all plants having the same genetic constitution: Among them, the exclusively vegetatively propagated [[Crocus sativus|saffron crocus]] (''Crocus sativus''). Also, the extremely rare Tasmanian shrub ''[[Lomatia tasmanica]]'' is a triploid sterile species.

There are few naturally occurring polyploid [[conifers]].<ref>{{cite journal | vauthors = Halabi K, Shafir A, Mayrose I | title = PloiDB: The plant ploidy database | journal = The New Phytologist | date = June 2023 | volume = 240 | issue = 3 | pages = 918–927 | pmid = 37337836 | doi = 10.1111/nph.19057 | doi-access = free }}</ref> One example is the Coast Redwood ''[[Sequoia sempervirens]]'', which is a hexaploid (6''x'') with 66 chromosomes (2''n'' = 6''x'' = 66), although the origin is unclear.<ref>{{cite journal |id={{INIST|13965465}} | vauthors = Ahuja MR, Neale DB |title=Origins of Polyploidy in Coast Redwood (''Sequoia sempervirens'' (D. Don) Endl.) and Relationship of Coast Redwood to other Genera of Taxodiaceae |journal=Silvae Genetica |volume=51 |pages=2–3 |year=2002 }}</ref>

Aquatic plants, especially the [[Monocotyledon]]s, include a large number of polyploids.<ref>{{cite journal |doi=10.1016/0304-3770(93)90071-4 |title=Studies of hybridization and chromosome number variation in aquatic angiosperms: Evolutionary implications |year=1993 | vauthors = Les DH, Philbrick CT |journal=Aquatic Botany |volume=44 |issue=2–3 |pages=181–228|bibcode=1993AqBot..44..181L }}</ref>

==== Crops ====
The induction of polyploidy is a common technique to overcome the sterility of a hybrid species during plant breeding. For example, [[triticale]] is the hybrid of [[wheat]] (''Triticum turgidum'') and [[rye]] (''Secale cereale''). It combines sought-after characteristics of the parents, but the initial hybrids are sterile. After polyploidization, the hybrid becomes fertile and can thus be further propagated to become triticale.

In some situations, polyploid crops are preferred because they are sterile. For example, many seedless fruit varieties are seedless as a result of polyploidy. Such crops are propagated using asexual techniques, such as [[grafting]].

Polyploidy in crop plants is most commonly induced by treating seeds with the chemical [[Colchicine#Botanical use and seedless fruit|colchicine]].

===== Examples =====

* Triploid crops: some [[apple]] varieties (such as [[Belle de Boskoop]], [[Jonagold]], [[Mutsu (apple)|Mutsu]], [[Ribston Pippin]]), [[banana]], [[citrus]], [[ginger]], [[watermelon]],<ref>{{cite news |last1=Karp |first1=David |title=Seedless Fruits Make Others Needless |url=https://www.theledger.com/story/news/2007/03/25/seedless-fruits-make-others-needless/25840915007/ |work=The Ledger |agency=The New York Times |date=25 March 2007 }}</ref> [[Crocus sativus|saffron crocus]], white pulp of coconut
* Tetraploid crops: very few [[apple]] varieties, [[durum]] or [[macaroni]] [[wheat]], [[cotton]], [[potato]], [[canola]]/[[rapeseed]], [[leek]], [[tobacco]], [[peanut]], [[kinnow]], [[Pelargonium]]
* Hexaploid crops: [[chrysanthemum]], bread [[wheat]], [[triticale]], [[oat]], [[kiwifruit]]<ref name=kiwifruit />
* Octaploid crops: [[strawberry]], [[dahlia]], [[pansies]], [[sugar cane]], oca (''[[Oxalis tuberosa]]'')<ref>{{cite book| vauthors = Emshwiller E |year=2006 |title= Documenting Domestication: New Genetic and Archaeological Paradigms |chapter= Origins of polyploid crops: The example of the octaploid tuber crop ''Oxalis tuberosa'' |publisher=University of California Press |location=Berkeley, CA | veditors = Zeder MA, Decker-Walters D, Emshwiller E, Bradley D, Smith BD |isbn=978-0-520-24638-6 |pages=153–168 }}</ref>
* Dodecaploid crops: some [[sugar cane]] hybrids<ref>{{cite journal | vauthors = Le Cunff L, Garsmeur O, Raboin LM, Pauquet J, Telismart H, Selvi A, Grivet L, Philippe R, Begum D, Deu M, Costet L, Wing R, Glaszmann JC, D'Hont A | display-authors = 6 | title = Diploid/polyploid syntenic shuttle mapping and haplotype-specific chromosome walking toward a rust resistance gene (Bru1) in highly polyploid sugarcane (2n approximately 12x approximately 115) | journal = Genetics | volume = 180 | issue = 1 | pages = 649–660 | date = September 2008 | pmid = 18757946 | pmc = 2535714 | doi = 10.1534/genetics.108.091355 }}</ref>

Some crops are found in a variety of ploidies: [[tulip]]s and [[lily|lilies]] are commonly found as both diploid and triploid; [[daylilies]] (''Hemerocallis'' cultivars) are available as either diploid or tetraploid; apples and [[kinnow|kinnow mandarins]] can be diploid, triploid, or tetraploid.