homology

American  

[huh-mol-uh-jee, hoh-] / həˈmɒl ə dʒi, hoʊ- /

noun

plural

homologies

1. the state of being homologous; homologous relation or correspondence.

2. Biology.

   1. a fundamental similarity based on common descent.

   2. a structural similarity of two segments of one animal based on a common developmental origin.

3. Chemistry. the similarity of organic compounds of a series in which each member differs from its adjacent compounds by a fixed increment, as by CH 2 .

4. Mathematics. a classification of figures according to certain topological properties.

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homology British  

/ həʊˈmɒlədʒɪ /

noun

1. the condition of being homologous

2. chem the similarities in chemical behaviour shown by members of a homologous series

3. zoology the measurable likenesses between animals, as used in grouping them according to the theory of cladistics

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homology Scientific  

/ hə-mŏl′ə-jē /

1. A homologous relationship or correspondence.

2. The relation of the chemical elements of a periodic family or group.

3. The relation of the organic compounds forming a homologous series.

4. A topological classification of configurations into distinct types that imposes an algebraic structure or hierarchy on families of geometric figures.

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Etymology

Origin of homology

1650–60; < Greek homología agreement, equivalent to homólog ( os ) homologous + -ia -y ³

Explanation

A good example of homology is the wing of a bird and the flipper of a whale, which have the same evolutionary origin. Consequently, they're in a similar place on the body and have some similar characteristics. Homology exists between any distinct things that are the same in some important way. The word comes from Greek homologia, meaning "agreement"; the combining form homo- means “same." In biology, homology exists between parts or structures that are similar in some way, including having the same evolutionary origin. This is different from analogy, which is a similarity that doesn't have a common evolutionary origin — such as the analogy between a bird's wing and a mosquito's: Both are used for flying, but they developed by independent paths.

Example Sentences

Co-author Roberto Hofmann noticed that, in addition to the red-green sensing domain, CcaS had a domain with homology to blue-light photosensors called phototropins.

From Science Daily • Sep. 21, 2023

After using some standard techniques to simplify the data, the team computed the persistent homology of the system by connecting the data points at different scales and examining the resulting simplicial complexes.

From Scientific American • Sep. 26, 2022

DNA analysis shows that emus and ostriches share more genetic homology with flying birds which live in the same region than with each other.

From Textbooks • Jun. 9, 2022

Serpell and other scientists tend to characterize this position as an overcorrection, but those who espouse it often begin by questioning the homology between dogs and wolves.

From Washington Post • Aug. 10, 2021

If, assuming descent, this homology were disturbed, and the systematic relationship done away with, for instance through saltatory evolution, the mere fact of descent would not bring the two species any nearer one another.

From Naturalism And Religion by Otto, Rudolf

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