Apomorphy and synapomorphy

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Phylogenies showing the terminology used to describe different patterns of ancestral and derived character or trait states. Synapomorphy.jpg
Phylogenies showing the terminology used to describe different patterns of ancestral and derived character or trait states.

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]

Contents

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".

Examples

Lampreys and sharks share some features, like a nervous system, that are not synapomorphic because they are also shared by invertebrates. In contrast, the presence of jaws and paired appendages [11] in both sharks and dogs, but not in lampreys or close invertebrate relatives, identifies these traits as synapomorphies. This supports the hypothesis that dogs and sharks are more closely related to each other than to lampreys.

Clade analysis

The concept of synapomorphy depends on a given clade in the tree of life. Cladograms are diagrams that depict evolutionary relationships within groups of taxa. These illustrations are accurate predictive device in modern genetics. They are usually depicted in either tree or ladder form. Synapomorphies then create evidence for historical relationships and their associated hierarchical structure. Evolutionarily, a synapomorphy is the marker for the most recent common ancestor of the monophyletic group consisting of a set of taxa in a cladogram. [12] What counts as a synapomorphy for one clade may well be a primitive character or plesiomorphy at a less inclusive or nested clade. For example, the presence of mammary glands is a synapomorphy for mammals in relation to tetrapods but is a symplesiomorphy for mammals in relation to one another—rodents and primates, for example. So the concept can be understood as well in terms of "a character newer than" (autapomorphy) and "a character older than" (plesiomorphy) the apomorphy: mammary glands are evolutionarily newer than vertebral column, so mammary glands are an autapomorphy if vertebral column is an apomorphy, but if mammary glands are the 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. [13] [14]

Related Research Articles

Cladistics is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics (synapomorphies) that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms worms or fishes were used within a strict cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. Radiation results in the generation of new subclades by bifurcation, but in practice sexual hybridization may blur very closely related groupings.

<span class="mw-page-title-main">Clade</span> Group of a common ancestor and all descendants

In biological phylogenetics, a clade, also known as a monophyletic group or natural group, is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. In the taxonomical literature, sometimes the Latin form cladus is used rather than the English form. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields.

<span class="mw-page-title-main">Monophyly</span> Property of a group of including all taxa descendant from a common ancestral species

In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of taxa which meets these criteria:

  1. the grouping contains its own most recent common ancestor, i.e. excludes non-descendants of that common ancestor
  2. the grouping contains all the descendants of that common ancestor, without exception

In biology, phylogenetics is the study of the evolutionary history of life using genetics, which is known as phylogenetic inference. It establishes the relationship between organisms with the empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram setting the hypothetical relationships between organisms and their evolutionary history.

In biology, phenetics, also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually with respect to morphology or other observable traits, regardless of their phylogeny or evolutionary relation. It is related closely to numerical taxonomy which is concerned with the use of numerical methods for taxonomic classification. Many people contributed to the development of phenetics, but the most influential were Peter Sneath and Robert R. Sokal. Their books are still primary references for this sub-discipline, although now out of print.

<span class="mw-page-title-main">Paraphyly</span> Type of taxonomic group

Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic with respect to the excluded subgroups. In contrast, a monophyletic grouping includes a common ancestor and all of its descendants.

<span class="mw-page-title-main">Systematics</span> Branch of biology

Systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees. Phylogenies have two components: branching order and branch length. Phylogenetic trees of species and higher taxa are used to study the evolution of traits and the distribution of organisms (biogeography). Systematics, in other words, is used to understand the evolutionary history of life on Earth.

<span class="mw-page-title-main">Cladogram</span> Diagram used to show relations among groups of organisms with common origins

A cladogram is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ancestors. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational phylogenetics are now very commonly used in the generation of cladograms, either on their own or in combination with morphology.

<span class="mw-page-title-main">Homology (biology)</span> Shared ancestry between a pair of structures or genes in different taxa

In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, regardless of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common ancestor after having been subjected to adaptive modifications for different purposes as the result of natural selection.

<span class="mw-page-title-main">Phylogenesis</span>

Phylogenesis is the biological process by which a taxon appears. The science that studies these processes is called phylogenetics.

<span class="mw-page-title-main">Outgroup (cladistics)</span>

In cladistics or phylogenetics, an outgroup is a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup, the set of organisms under study, and is distinct from sociological outgroups. The outgroup is used as a point of comparison for the ingroup and specifically allows for the phylogeny to be rooted. Because the polarity (direction) of character change can be determined only on a rooted phylogeny, the choice of outgroup is essential for understanding the evolution of traits along a phylogeny.

In phylogenetics and computational phylogenetics, maximum parsimony is an optimality criterion under which the phylogenetic tree that minimizes the total number of character-state changes. Under the maximum-parsimony criterion, the optimal tree will minimize the amount of homoplasy. In other words, under this criterion, the shortest possible tree that explains the data is considered best. Some of the basic ideas behind maximum parsimony were presented by James S. Farris in 1970 and Walter M. Fitch in 1971.

In phylogenetics, long branch attraction (LBA) is a form of systematic error whereby distantly related lineages are incorrectly inferred to be closely related. LBA arises when the amount of molecular or morphological change accumulated within a lineage is sufficient to cause that lineage to appear similar to another long-branched lineage, solely because they have both undergone a large amount of change, rather than because they are related by descent. Such bias is more common when the overall divergence of some taxa results in long branches within a phylogeny. Long branches are often attracted to the base of a phylogenetic tree, because the lineage included to represent an outgroup is often also long-branched. The frequency of true LBA is unclear and often debated, and some authors view it as untestable and therefore irrelevant to empirical phylogenetic inference. Although often viewed as a failing of parsimony-based methodology, LBA could in principle result from a variety of scenarios and be inferred under multiple analytical paradigms.

In phylogenetics, a primitive character, trait, or feature of a lineage or taxon is one that is inherited from the common ancestor of a clade and has undergone little change since. Conversely, a trait that appears within the clade group is called advanced or derived. A clade is a group of organisms that consists of a common ancestor and all its lineal descendants.

<span class="mw-page-title-main">Plesiomorphy and symplesiomorphy</span> Ancestral character or trait state shared by two or more taxa

In phylogenetics, a plesiomorphy and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades.

<span class="mw-page-title-main">Autapomorphy</span> Distinctive feature, known as a derived trait, that is unique to a given taxon

In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to the focal taxon. It can therefore be considered an apomorphy in relation to a single taxon. The word autapomorphy, introduced in 1950 by German entomologist Willi Hennig, is derived from the Greek words αὐτός, autos "self"; ἀπό, apo "away from"; and μορφή, morphḗ = "shape".

Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional method, by which taxon names are defined by a type, which can be a specimen or a taxon of lower rank, and a description in words. Phylogenetic nomenclature is regulated currently by the International Code of Phylogenetic Nomenclature (PhyloCode).

<span class="mw-page-title-main">Character evolution</span>

Character evolution is the process by which a character or trait evolves along the branches of an evolutionary tree. Character evolution usually refers to single changes within a lineage that make this lineage unique from others. These changes are called character state changes and they are often used in the study of evolution to provide a record of common ancestry. Character state changes can be phenotypic changes, nucleotide substitutions, or amino acid substitutions. These small changes in a species can be identifying features of when exactly a new lineage diverged from an old one.

<span class="mw-page-title-main">Homoplasy</span> Gain or loss of the same feature independently in separate lineages during evolution

Homoplasy, in biology and phylogenetics, is the term used to describe a feature that has been gained or lost independently in separate lineages over the course of evolution. This is different from homology, which is the term used to characterize the similarity of features that can be parsimoniously explained by common ancestry. Homoplasy can arise from both similar selection pressures acting on adapting species, and the effects of genetic drift.

This glossary of genetics and evolutionary biology is a list of definitions of terms and concepts used in the study of genetics and evolutionary biology, as well as sub-disciplines and related fields, with an emphasis on classical genetics, quantitative genetics, population biology, phylogenetics, speciation, and systematics. It has been designed as a companion to Glossary of cellular and molecular biology, which contains many overlapping and related terms; other related glossaries include Glossary of biology and Glossary of ecology.

References

  1. 1 2 Roderick D.M. Page; Edward C. Holmes (14 July 2009). Molecular Evolution: A Phylogenetic Approach. John Wiley & Sons. ISBN   978-1-4443-1336-9.
  2. ↑ Futuyma, Douglas J.; Kirkpatrick, Mark (2017). "Tree of life". Evolution (4th ed.). Sunderland, Mass.: Sinauer Associates. pp. 27–53.
  3. 1 2 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. 1 2 Kitching, Ian J.; Forey, Peter L.; Williams, David M. (2001). "Cladistics". In Levin, Simon A. (ed.). Encyclopedia of Biodiversity (2nd ed.). Elsevier. pp. 33–45. doi:10.1016/B978-0-12-384719-5.00022-8. ISBN   9780123847201 . Retrieved 29 August 2021.)
  6. ↑ Hillis, David M.; Sadava, David; Hill, Richard W.; Price, Mary V. (2014). "Reconstructing and using phylogenies". Principles of Life (2nd ed.). Sunderland, Mass.: Sinauer Associates. pp. 325–342. ISBN   978-1464175121.
  7. ↑ Currie PJ, Padia K (1997). Encyclopedia of Dinosaurs. Elsevier. p. 543. ISBN   978-0-08-049474-6.
  8. ↑ Concise Encyclopedia Biology . Tubingen, DEU: Walter de Gruyter. 1996. p.  366. ISBN   9783110106619.
  9. ↑ Barton N, Briggs D, Eisen J, Goldstein D, Patel N (2007). "Phylogenetic Reconstruction". Evolution. Cold Spring Harbor Laboratory Press.
  10. 1 2 Baum, David (2008). "Trait Evolution on a Phylogenetic Tree: Relatedness, Similarity, and the Myth of Evolutionary Advancement". Nature Education. 1 (1): 191.
  11. ↑ andrewgillis (2016-04-19). "Gills, fins and the evolution of vertebrate paired appendages". the Node. Retrieved 2024-06-09.
  12. ↑ Novick LR, Catley KM. Understanding phylogenies in biology: the influence of a Gestalt perceptual principle. J Exp Psychol Appl. 2007;13:197–223.
  13. ↑ Roderick D.M. Page; Edward C. Holmes (14 July 2009).  Molecular Evolution: A Phylogenetic Approach. John Wiley & Sons.  ISBN   978-1-4443-1336-9.
  14. ↑ Calow PP (2009). Encyclopedia of Ecology and Environmental Management. John Wiley & Sons. ISBN   978-1-4443-1324-6. OCLC   1039167559.
  15. ↑ Williams D, Schmitt M, Wheeler Q (July 2016). The Future of Phylogenetic Systematics: The Legacy of Willi Hennig. Cambridge University Press. ISBN   978-1-107-11764-8.
  16. ↑ Simpson MG (9 August 2011). Plant Systematics. Amsterdam. ISBN   9780080514048.{{cite book}}: |work= ignored (help)CS1 maint: location missing publisher (link)
  17. ↑ Russell PJ, Hertz PE, McMillan B (2013). Biology: The Dynamic Science. Cengage Learning. ISBN   978-1-285-41534-5.
  18. ↑ Lipscomb D (1998). "Basics of Cladistic Analysis" (PDF). Washington D.C.: George Washington University.
  19. ↑ Choudhuri S (2014-05-09). Bioinformatics for Beginners: Genes, Genomes, Molecular Evolution, Databases and Analytical Tools (1st ed.). Academic Press. p. 51. ISBN   978-0-12-410471-6. OCLC   950546876.
  20. ↑ 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.
  21. ↑ Gauger A (April 17, 2012). "Similarity Happens! The Problem of Homoplasy". Evolution Today & Science News.
  22. ↑ Sanderson MJ, Hufford L (21 October 1996). Homoplasy: The Recurrence of Similarity in Evolution. Elsevier. ISBN   978-0-08-053411-4. OCLC   173520205.
  23. ↑ Brandley MC, Warren DL, Leaché AD, McGuire JA (April 2009). "Homoplasy and clade support". Systematic Biology. 58 (2): 184–98. doi: 10.1093/sysbio/syp019 . PMID   20525577.
  24. ↑ Archie JW (September 1989). "Homoplasy Excess Ratios: New Indices for Measuring Levels of Homoplasy in Phylogenetic Systematics and a Critique of the Consistency Index". Systematic Biology. 38 (1): 253–269. doi:10.2307/2992286. JSTOR   2992286.
  25. ↑ Wake DB, Wake MH, Specht CD (February 2011). "Homoplasy: from detecting pattern to determining process and mechanism of evolution". Science. 331 (6020): 1032–5. Bibcode:2011Sci...331.1032W. doi:10.1126/science.1188545. PMID   21350170. S2CID   26845473.
  26. ↑ Avise JC, Robinson TJ (June 2008). "Hemiplasy: a new term in the lexicon of phylogenetics". Systematic Biology. 57 (3): 503–7. doi: 10.1080/10635150802164587 . PMID   18570042.
  27. ↑ Copetti D, Búrquez A, Bustamante E, Charboneau JL, Childs KL, Eguiarte LE, Lee S, Liu TL, McMahon MM, Whiteman NK, Wing RA, Wojciechowski MF, Sanderson MJ (November 2017). "Extensive gene tree discordance and hemiplasy shaped the genomes of North American columnar cacti". Proceedings of the National Academy of Sciences of the United States of America. 114 (45): 12003–12008. Bibcode:2017PNAS..11412003C. doi: 10.1073/pnas.1706367114 . PMC   5692538 . PMID   29078296.
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