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Homology
existence of shared ancestry between a pair of structures, or genes, in different taxa / From Wikipedia, the free encyclopedia
For the mathematical idea, see Homology (mathematics).
A homologous[1] trait is any characteristic which is derived by evolution from a common ancestor. This is contrasted to analogous traits: similarities between organisms that were evolved separately.
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The term existed before 1859, but got its modern meaning after Darwin established the idea of common descent.[2]p45 The pre-Darwinian naturalists Cuvier, Geoffroy and Richard Owen, also used the idea.
A homologous trait is often called a homologue (also spelled homolog). In genetics, the term "homologue" is used both to refer to a homologous protein, and to the gene (DNA sequence) encoding it.