Editing Hybrid (biology) (section)

===In evolution===
Hybridization between species plays an important role in evolution, though there is much debate about its significance. Roughly 25% of plants and 10% of animals are known to form hybrids with at least one other species.<ref>{{cite journal |last1=Quilodran |first1=Claudio S. |last2=Montoya-Burgos |first2=Juan I. |last3=Currat |first3=Matthias |title=Harmonizing hybridization dissonance in conservation |journal=Communications Biology |date=2020 |volume=3 |issue=391|page=391 |doi=10.1038/s42003-020-1116-9 |pmid=32694629 |pmc=7374702 }}</ref> One example of an adaptive benefit to hybridization is that hybrid individuals can form a "bridge" transmitting potentially helpful genes from one species to another when the hybrid [[backcrossing|backcrosses]] with one of its parent species, a process called [[introgression]].<ref>{{cite journal |last1=Twyford |first1=A D |last2=Ennos |first2=R A |title=Next-generation hybridization and introgression |journal=Heredity |date=2012 |volume=108|issue=3 |pages=179–189 |doi=10.1038/hdy.2011.68 |pmid=21897439 |pmc=3282392 |bibcode=2012Hered.108..179T }}</ref> Hybrids can also cause [[speciation]], either because the hybrids are genetically incompatible with their parents and not each other, or because the hybrids occupy a different niche than either parent. 

Hybridization is a particularly common mechanism for speciation in plants, and is now known to be fundamental to the evolutionary history of plants.<ref>{{cite journal |last1=Soltis |first1=Pamela S |last2=Soltis |first2=Douglas E. |title=The Role of Hybridization in Plant Speciation |journal=Annual Review of Plant Biology |date=2009 |volume=60 |issue=1 |pages=561–568|doi=10.1146/annurev.arplant.043008.092039 |pmid=19575590 |bibcode=2009AnRPB..60..561S }}</ref> Plants frequently form [[polyploid]]s, individuals with more than two copies of each chromosome. Whole genome doubling has occurred repeatedly in plant evolution. When two plant species hybridize, the hybrid may double its chromosome count by incorporating the entire nuclear genome of both parents, resulting in offspring that are reproductively incompatible with either parent because of different chromosome counts.