Editing Speciation (section)

=== Speciation via polyploidy ===
[[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]]. In plants, this can effectively be a new species, reproductively isolated from its parents, and able to reproduce.]]
{{main|Polyploid}}

[[Polyploid]]y is a mechanism that has caused many rapid speciation events in [[sympatry]] because offspring of, for example, tetraploid x diploid matings often result in triploid sterile progeny.<ref>{{cite journal |last1=Ramsey |first1=Justin |last2=Schemske |first2=Douglas W. |date=November 1998 |title=Pathways, Mechanisms, and Rates of Polyploid Formation in Flowering Plants |journal=[[Annual Review of Ecology, Evolution, and Systematics|Annual Review of Ecology and Systematics]] |volume=29 |pages=467–501 |doi=10.1146/annurev.ecolsys.29.1.467|bibcode=1998AnRES..29..467R |s2cid=31637733 |url=https://pdfs.semanticscholar.org/4696/87a97276b274bba6469e7979dfc99a23e4cc.pdf |archive-url=https://web.archive.org/web/20200608074533/https://pdfs.semanticscholar.org/4696/87a97276b274bba6469e7979dfc99a23e4cc.pdf |url-status=dead |archive-date=2020-06-08 }}</ref> However, among plants, not all polyploids are reproductively isolated from their parents, and gene flow may still occur, such as through triploid hybrid x diploid matings that produce tetraploids, or matings between [[meiosis|meiotically unreduced]] gametes from diploids and gametes from tetraploids (see also [[hybrid speciation]]).{{Citation needed|date=November 2023}}

It has been suggested that many of the existing plant and most animal species have undergone an event of polyploidization in their evolutionary history.<ref>{{cite journal |last1=Otto |first1=Sarah P. |author-link1=Sarah Otto |last2=Whitton |first2=Jeannette |date=December 2000 |title=Polyploid Incidence and Evolution |journal=[[Annual Review of Genetics]] |volume=34 |pages=401–437 |doi=10.1146/annurev.genet.34.1.401 |pmid=11092833|url=http://www.zoology.ubc.ca/~otto/Reprints/OttoWhitton2000.pdf |citeseerx=10.1.1.323.1059 }}</ref><ref name="Comai_2005">{{cite journal |last1=Comai |first1=Luca |author-link1=Luca Comai |date=November 2005 |title=The advantages and disadvantages of being polyploid |journal=[[Nature Reviews Genetics]] |volume=6 |issue=11 |pages=836–846 |doi=10.1038/nrg1711 |pmid=16304599|s2cid=3329282 }}</ref> Reproduction of successful polyploid species is sometimes asexual, by [[parthenogenesis]] or [[apomixis]], as for unknown reasons many asexual organisms are polyploid. Rare instances of polyploid mammals are known, but most often result in prenatal death. <ref>{{Cite journal |last1=Mezzasalma |first1=Marcello |last2=Brunelli |first2=Elvira |last3=Odierna |first3=Gaetano |last4=Guarino |first4=Fabio Maria |date=2023-03-12 |title=Evolutionary and Genomic Diversity of True Polyploidy in Tetrapods |journal=Animals |volume=13 |issue=6 |pages=1033 |doi=10.3390/ani13061033 |doi-access=free |issn=2076-2615 |pmid=36978574|pmc=10044425 }}</ref>