Relation between biological objects that resemble or are related to each other sufficiently to warrant a comparison.
Similarity that results from common evolutionary origin.
This broad definition encompasses all the working definitions proposed so far in the literature.
Similarity that results from independent evolution.
Homology and homocracy are not mutually exclusive. The homology relationships of patterning genes may be unresolved and thus may include orthologues and paralogues.
Similarity that is characterized by the organization of anatomical structures through the expression of homologous or identical patterning genes.
inferred from gene expression similarity
Convergence usually implies a notion of adaptation.
Homoplasy that involves different underlying mechanisms or structures.
Can be applied for features present in closely related organisms but not present continuously in all the members of the lineage.
Homoplasy that involves homologous underlying mechanisms or structures.
Homology that is defined by similarity with regard to selected structural parameters.
Homology that is defined by common descent.
Applicable only to morphology. A certain degree of ambiguity is accepted between biological homology and parallelism.
Homology that is defined by sharing of a set of developmental constraints, caused by locally acting self-regulatory mechanisms of differentiation, between individualized parts of the phenotype.
Homoplasy that involves phenotypes similar to those seen in ancestors within the lineage.
Structural homology that is detected by similarity in content and organization between chromosomes.
Historical homology that involves genes that diverged after a duplication event.
Paralogy that involves sets of syntenic blocks.
Syntenic homology that involves chromosomes of different species.
Structural homology that involves complex structures from which only a fraction of the elements that can be isolated are separately homologous.
Structural homology that is detected at the level of the 3D protein structure, but maybe not at the level of the amino acid sequence.
Structural homology that involves a pseudogenic feature and its functional ancestor.
Historical homology that involves genes that diverged after a speciation event.
The term is sometimes also used for anatomical structures.
Historical homology that is characterized by an interspecies (horizontal) transfer since the common ancestor.
The term is sometimes also used for anatomical structures (e.g. in case of a symbiosis).
Historical homology that involves two members sharing no other homologs in the lineages considered.
Orthology that involves two genes that did not experience any duplication after the speciation event that created them.
Relationship between recognizably corresponding characters that occurs in two or more taxa and have different generative bases.
Paralogy that results from a whole genome duplication event.
Paralogy that results from a lineage-specific duplication subsequent to a given speciation event.
Paralogy that results from a duplication preceding a given speciation event.
1:many orthology that involves a gene in species A and one of its ortholog in species B, when duplications more recent than the species split have occurred in species B but not in species A.
1:many orthology that involves a gene in species A and its ortholog in species B, when duplications more recent than the species split have occurred in species A but not in species B.
Iterative homology that involves structures arranged along the main body axis.
Biological homology that is characterized by changes, over evolutionary time, in the rate or timing of developmental events of homologous structures.
Heterochronous homology that is produced by a retention in adults of a species of traits previously seen only in juveniles.
Heterochronous homology that is produced by a maturation of individuals of a species past adulthood, which take on hitherto unseen traits.
Paedomorphosis that is produced by precocious sexual maturation of an organism still in a morphologically juvenile stage.
Paedomorphosis that is produced by a retardation of somatic development.
Convergence that results from co-evolution usually involving an evolutionary arms race.
Orthology that involves two genes when duplications more recent than the species split have occurred in one species but not the other.
Historical homology that involves two members of a larger set of homologs.
Historical homology that involves a structure that has no other homologs in the species in which it is defined, and several homologous structures in another species.
Historical homology that is based on recent shared ancestry, characterizing a monophyletic group.
Historical homology that is based on distant shared ancestry.
This term is usually contrasted to apomorphy.
Homocracy that involves morphologically and phylogenetically disparate structures that are the result of parallel evolution.
Used for structures in distantly related taxa.
Historical homology that is characterized by topological discordance between a gene tree and a species tree attributable to the phylogenetic sorting of genetic polymorphisms across successive nodes in a species tree.
Historical homology that involves not recombining and subsequently differentiated sex chromosomes.
Historical homology that involves the chromosomes able to pair (synapse) during meiosis.
Orthology that involves two genes that experienced duplications more recent than the species split that created them.
Paralogy that involves genes from the same species.
Paralogy that involves genes from different species.
The genes have diverged before a speciation event.
Paedomorphosis that is produced by delayed growth of immature structures into the adult form.
Peramorphosis that is produced by a delay in the offset of development.
Xenology that results, not from the transfer of a gene between two species, but from a hybridization of two species.
Orthology that involves functional equivalent genes with retention of the ancestral function.
Paralogy that is characterized by duplication of adjacent sequences on a chromosome segment.
Parallelism that involves morphologically very similar structures, occurring only within some members of a taxon and absent in the common ancestor (which possessed the developmental basis to develop this character).
Used for structures in closely related taxa.
Cannot be used when orthologous patterning gene are organizing obviously non-homologous structures in different organisms due for example to pleiotropic functions of these genes.
Homocracy that involves recognizably corresponding characters that occurs in two or more taxa, or as a repeated unit within an individual.
Between-species paralogy that involves single copy paralogs resulting from reciprocal gene loss.
The genes are actually paralogs but appear to be orthologous due to differential, lineage-specific gene loss.
These genes may come out as paralogs in a single-genome analysis.
Xenology that involves genes that ended up in a given genome as a result of a combination of vertical inheritance and horizontal gene transfer.
Historical homology that involves functional equivalent genes with retention of the ancestral function.
This may include examples of orthology, paralogy and xenology.
Historical homology that involves orthologous pairs of interacting molecules in different organisms.
Similarity that is characterized by interchangeability in function.
Biological homology that involves parts of the same organism.
Xenology that is characterized by multiple horizontal transfer events, resulting in the presence of two or more copies of the foreign gene in the host genome.
Paralogy that is characterized by extra similarity between paralogous sequences resulting from concerted evolution.
This phenomenon is usually due to gene conversion process.
Structural homology that involves structures with the same or similar relative positions.
Theissen (2005) mentions that some authors may consider homotopy to be distinct from homology, but this is not the standard use.
Biological homology that involves an ectopic structure and the normally positioned structure.
On a long term, it is hard to distinguish allopolyploidy from whole genome duplication.
Synology that results from allopolyploidy.
Iterative homology that involves two structures, one of which originated as a duplicate of the other and co-opted the expression of patterning genes of the ancestral structure.
Historical homology that involves orthologous pairs of transcription factors and downstream regulated genes in different organisms.