epis·​ta·​sis i-ˈpi-stə-səs How to pronounce epistasis (audio)
plural epistases i-ˈpi-stə-ˌsēz How to pronounce epistasis (audio)
: suppression of the effect of a gene by a nonallelic gene
epistatic adjective

Examples of epistasis in a Sentence

Recent Examples on the Web And indeed, bioengineering is where epistasis might cause us the most trouble. C. Brandon Ogbunu, Quanta Magazine, 31 July 2023 That is, there are many important genetic stories to tell without epistasis. C. Brandon Ogbunu, Quanta Magazine, 31 July 2023 To put it differently, a full embrace of epistasis can feel almost nihilistic. C. Brandon Ogbunu, Quanta Magazine, 31 July 2023 Frequency dependence and epistasis can impact on linear assumptions within a statistical genetic model. Razib Khan, Discover Magazine, 16 Sep. 2010 In particular, epistasis manifesting as compensatory deleterious mutations. Razib Khan, Discover Magazine, 13 Jan. 2011 This phenomenon is known as epistasis. Ed Yong, Discover Magazine, 17 Feb. 2011 The reason for outbreeding depression is most likely going to be some sort of antagonistic epistasis, deleterious gene-gene interactions. Razib Khan, Discover Magazine, 20 July 2012 On the one hand epistasis refers to physical relationships between genes. Razib Khan, Discover Magazine, 27 July 2010

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'epistasis.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


epi- + -stasis, after earlier epistatic, by analogy with metastatic : metastatis and like pairs

Note: The term epistatic was introduced, along with hypostatic, by the English biologist William Bateson (1861-1926) in "Facts Limiting the Theory of Heredity" ("Address delivered at the International Zoological Congress, before the Section of Cytology and Heredity, August 23, 1907"), Science, series 2, vol. 26 (July-December, 1907), issue of November 15, 1907, p. 653: "Till lately we spoke of the relations between the gray color of the mouse to the black color in terms of dominance …We can perhaps best express the relation between the gray and the black by the use of metaphor 'higher and lower,' and I therefore suggest the term epistatic as applicable to characters which have to be, as it were, lifted off in order to permit the lower or hypostatic character to appear."

First Known Use

circa 1917, in the meaning defined above

Time Traveler
The first known use of epistasis was circa 1917

Dictionary Entries Near epistasis

Cite this Entry

“Epistasis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/epistasis. Accessed 25 Jul. 2024.

Medical Definition


epis·​ta·​sis i-ˈpis-tə-səs How to pronounce epistasis (audio)
plural epistases -ˌsēz How to pronounce epistasis (audio)
: suppression of a secretion or discharge
: a scum on the surface of urine
: suppression of the effect of a gene by a nonallelic gene
the role of epistasis in polygenic inheritance

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