homology

noun ho·mol·o·gy \ hō-ˈmä-lə-jē , hə- \

Definition of homology

plural homologies
1 : a similarity often attributable to common origin
2 a : likeness in structure between parts of different organisms (such as the wing of a bat and the human arm) due to evolutionary differentiation from a corresponding part in a common ancestor — compare analogy
b : correspondence in structure between a series of parts (such as vertebrae) in the same individual
3 : similarity of nucleotide or amino acid sequence (as in nucleic acids or proteins)
4 : a branch of the theory of topology concerned with partitioning space into geometric components (such as points, lines, and triangles) and with the study of the number and interrelationships of these components especially by the use of group theory called also homology theory; compare cohomology

Recent Examples of homology from the Web

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Did You Know?

The similarity of a structure or function of parts of different origins based on their descent from a common evolutionary ancestor is homology. Analogy, by contrast, is a functional similarity of structure that is based on mere similarity of use. For example, the forelimbs of humans, bats, and deer are homologous; the form of construction and the number of bones in each are almost identical and represent adaptive modifications of the forelimb structure of their shared ancestor. The wings of birds and insects, on the other hand, are merely analogous; both are used for flight, but they do not share a common ancestral origin.

First Known Use of homology

circa 1656

Other Biochemistry Terms


Medical Dictionary

homology

noun ho·mol·o·gy \ hō-ˈmäl-ə-jē, hə- \

medical Definition of homology

plural homologies
1 a : likeness in structure between parts of different organisms due to evolutionary differentiation from the same or a corresponding part of a remote ancestor — compare analogy, homomorphy
b : correspondence in structure between different parts of the same individual
2 a : the relation existing between chemical compounds in a series whose successive members have in composition a regular difference especially of one carbon and two hydrogen atoms CH2
b : the relation existing among elements in the same group of the periodic table
c : similarity of nucleotide or amino acid sequence (as in nucleic acids or proteins)


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