homology

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homology
1. The basic similarity of a particular structure in different organisms: it usually results from their descent from a common ancestor. Two organs sharing a similar position, a similar histological appearance, and a similar embryonic development are said to be homologous organs irrespective of their superficial appearance and function in the adult. See also homologous chromosomes.

2. The extent to which two DNA or amino acid sequences resemble one another.

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