Apomorphy and synapomorphy

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Synapomorphy and apomorphy
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Phylogenies showing the terminology used to describe different patterns of ancestral and derived character or trait states.[1]

In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy).[2][3][4] A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor.[1][5][3][6][7][8][9] In cladistics, synapomorphy implies homology.[5]

Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur.[10] Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals.[10]

Etymology

The word synapomorphy—coined by German entomologist Willi Hennig—is derived from the Ancient Greek words σύν (sún), meaning "with, together"; ἀπό (apó), meaning "away from"; and μορφή (morphḗ), meaning "shape, form".

Clade analysis

The concept of synapomorphy depends on a given clade in the tree of life.

apomorphy
being considered then vertebral column is a plesiomorphy.

Relations to other terms

These phylogenetic terms are used to describe different patterns of ancestral and derived character or trait states as stated in the above diagram in association with apomorphies and synapomorphies.[12][13]

  • Symplesiomorphy
    – an ancestral trait shared by two or more taxa.
    • Plesiomorphy – a symplesiomorphy discussed in reference to a more derived state.
    • Pseudoplesiomorphy – is a trait that cannot be identified as neither a plesiomorphy nor an apomorphy that is a reversal.[14]
  • Reversal – is a loss of derived trait present in ancestor and the reestablishment of a plesiomorphic trait.
  • Convergence – independent evolution of a similar trait in two or more taxa.
  • Apomorphy – a derived trait. Apomorphy shared by two or more taxa and inherited from a common ancestor is synapomorphy. Apomorphy unique to a given taxon is autapomorphy.[15][16][17][18]
    • Synapomorphy/homology – a derived trait that is found in some or all terminal groups of a clade, and inherited from a common ancestor, for which it was an autapomorphy (i.e., not present in its immediate ancestor).
    • Underlying synapomorphy – a synapomorphy that has been lost again in many members of the clade. If lost in all but one, it can be hard to distinguish from an autapomorphy.
    • Autapomorphy – a distinctive derived trait that is unique to a given taxon or group.[19]
  • Homoplasy in biological systematics is when a trait has been gained or lost independently in separate lineages during evolution. This convergent evolution leads to species independently sharing a trait that is different from the trait inferred to have been present in their common ancestor.[20][21][22]
    • Parallel homoplasy – derived trait present in two groups or species without a common ancestor due to convergent evolution.[23]
    • Reverse homoplasy – trait present in an ancestor but not in direct descendants that reappears in later descendants.[24]
  • Hemiplasy is the case where a character that appears homoplastic given the species tree actually has a single origin on the associated gene tree.[25][26] Hemiplasy reflects gene tree-species tree discordance due to the multispecies coalescent.

References

  1. ^ .
  2. ^ Futuyma, Douglas J.; Kirkpatrick, Mark (2017). "Tree of life". Evolution (4th ed.). Sunderland, Mass.: Sinauer Associates. pp. 27–53.
  3. ^ a b Futuyma, Douglas J.; Kirkpatrick, Mark (2017). "Phylogeny: The unity and diversity of life". Evolution (4th ed.). Sunderland, Mass.: Sinauer Associates. pp. 401–429.
  4. ^ "Reconstructing trees: Cladistics". Understanding Evolution. University of California Museum of Paleontology. 5 May 2021. Retrieved 16 October 2021.
  5. ^ . Retrieved 29 August 2021.)
  6. .
  7. .
  8. .
  9. ^ Barton N, Briggs D, Eisen J, Goldstein D, Patel N (2007). "Phylogenetic Reconstruction". Evolution. Cold Spring Harbor Laboratory Press.
  10. ^ a b Baum, David (2008). "Trait Evolution on a Phylogenetic Tree: Relatedness, Similarity, and the Myth of Evolutionary Advancement". Nature Education. 1 (1): 191.
  11. ^ Novick LR, Catley KM. Understanding phylogenies in biology: the influence of a Gestalt perceptual principle. J Exp Psychol Appl. 2007;13:197–223.
  12. .
  13. .
  14. .
  15. ISBN 9780080514048. {{cite book}}: |work= ignored (help)CS1 maint: location missing publisher (link
    )
  16. .
  17. ^ Lipscomb D (1998). "Basics of Cladistic Analysis" (PDF). Washington D.C.: George Washington University.
  18. OCLC 950546876
    .
  19. ^ Appel, Ron D.; Feytmans, Ernest. Bioinformatics: a Swiss Perspective."Chapter 3: Introduction of Phylogenetics and its Molecular Aspects." World Scientific Publishing Company, 1st edition. 2009.
  20. ^ Gauger A (April 17, 2012). "Similarity Happens! The Problem of Homoplasy". Evolution Today & Science News.
  21. OCLC 173520205
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  25. PMID 18570042
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  26. .

External links