Editing Monophyly (section)

== Definitions ==
On the broadest scale, definitions fall into two groups.
* [[Willi Hennig]] (1966:148) defined monophyly as groups based on [[synapomorphy]] (in contrast to paraphyletic groups, based on [[symplesiomorphy]], and polyphyletic groups, based on [[convergent evolution|convergence]]).  Some authors have sought to define monophyly to include paraphyly as any two or more groups sharing a common ancestor.<ref name="Aubert-2015" /><ref name="Colless-1972">{{Cite journal
 | last1 = Colless | first1 = Donald H.
 |date=March 1972
 | title = Monophyly
 | journal = Systematic Zoology
 | volume = 21
 | issue = 1
 | pages = 126–128
 | doi = 10.2307/2412266
 | jstor=2412266
}}</ref><ref name="Envall-2008">{{cite journal
 | doi = 10.1111/j.1095-8312.2008.00984.x
 | title = On the difference between mono-, holo-, and paraphyletic groups: a consistent distinction of process and pattern
 | year = 2008
 | author = Envall, Mats
 | journal = Biological Journal of the Linnean Society
 | volume = 94
 | pages = 217–220 | doi-access = free
 }}</ref><ref name="Ashlock-1971">{{Cite journal
| last = Ashlock | first = Peter D.
|date=March 1971
| title = Monophyly and Associated Terms
| journal = Systematic Zoology
| volume = 20
| issue = 1
| pages = 63–69
| doi = 10.2307/2412223
| jstor=2412223
}}</ref> However, this broader definition encompasses both monophyletic and paraphyletic groups as defined above. Therefore, most scientists today restrict the term "monophyletic" to refer to groups consisting of all the descendants of one (hypothetical) common ancestor.<ref name="Hennig-1999"/> However, when considering taxonomic groups such as genera and species, the most appropriate nature of their common ancestor is rather a population.  Assuming that it would be one individual or mating pair is unrealistic for sexually reproducing species, which are by definition interbreeding populations.<ref name="Simpson-1961">{{cite book |last=Simpson |first=George |url=https://archive.org/details/principlesofanim0000simp |title=Principles of Animal Taxonomy |publisher=Columbia University Press |year=1990 |isbn=978-0-231-09650-8 |location=New York |url-access=registration}}</ref>
* Monophyly (or holophyly) and associated terms are restricted to discussions of taxa, and are not necessarily accurate when used to describe what Hennig called tokogenetic relationships – now referred to as genealogies.  Some argue that using a broader definition, such as a species and all its descendants, does not really work to define a genus.<ref name="Simpson-1961"/> The loose definition also fails to recognize the relations of all organisms.<ref>{{Cite web|url=https://www.mun.ca/biology/scarr/Taxon_types.htm|title=Monophyletic, Polyphyletic, & Paraphyletc Taxa|last=Carr|first=Steven M|website=www.mun.ca|access-date=2018-02-23}}</ref> According to D. M. Stamos, a satisfactory cladistic definition of a species or genus is impossible because many species (and even genera) may form by "budding" from an existing species, leaving the parent species paraphyletic; or the species or genera may be the result of [[hybrid speciation]].<ref>{{cite book|last=Stamos|first=D.N.|title=The species problem : biological species, ontology, and the metaphysics of biology|year=2003|publisher=Lexington Books|location=Lanham, Md. [u.a.]|isbn=978-0739105030|pages=261–268|url=https://books.google.com/books?id=jPAjv5FsKMYC&q=defining+species+cladistically%27&pg=PA260}}</ref>
The concepts of monophyly, [[paraphyly]], and [[polyphyly]] have been used in deducing key genes for [[DNA barcoding|barcoding]] of diverse group of species.<ref>{{cite journal |doi=10.1016/j.gene.2019.143967 |title=Diagnosis of mitogenome for robust phylogeny: A case of Cypriniformes fish group |journal=Gene |volume=713 |pages=143967 |year=2019 |last1=Parhi J., Tripathy P.S., Priyadarshi, H. |first1=Mandal S.C., Pandey P.K. |pmid=31279710 |s2cid=195828782 }}</ref>