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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 ...
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 . [ 1 ]
Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy all mean a trait shared between species because they share an ancestral species. [a] Apomorphic and synapomorphic characteristics convey much information about evolutionary clades and can be used to define taxa. However, plesiomorphic and symplesiomorphic characteristics cannot.
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 ...
Patterns such as these lead many cladists to consider the concept of homology and the concept of synapomorphy to be equivalent. [ 25 ] [ 24 ] Some cladists follow the pre-cladistic definition of homology of Haas and Simpson, [ 26 ] and view both synapomorphies and symplesiomorphies as homologous character states.
Homoplasy is the term used to describe a feature that has been gained or lost independently in separate lineages over the course of evolution. 1858, Paleontologist Heinrich Georg Bronn (1800–1862) published a hypothetical tree to illustrating the paleontological "arrival" of new, similar species. following the extinction of an older species.
There is evidence of both homoplasmic and heteroplasmic inherited mutations that lead to disease, though heteroplasmic mutations typically are a precursor to homoplasmic disease.
When this happens, a phylogenetic analysis may erroneously interpret this homoplasy as a synapomorphy (i.e., evolving once in the common ancestor of the two lineages). The opposite effect may also be observed, in that if two (or more) branches exhibit particularly slow evolution among a wider, fast evolving group, those branches may be ...