plei·​ot·​ro·​py plī-ˈä-trə-pē How to pronounce pleiotropy (audio)
: the phenomenon of a single gene influencing two or more distinct phenotypic traits : the quality or state of being pleiotropic
In genetics, there's a concept called pleiotropy, which posits that a single gene can influence multiple traits. [Steven] Tanksley suggests there's substantial evidence that at least some domesticated fruits selected for greater size were also altered in shape because both traits were controlled by the same selected gene or set of genes.Scott LeFee

Example Sentences

Recent Examples on the Web There is no doubt that even simple genetic abnormalities may cause many phenotypic consequences; this is called pleiotropy. Jessica Riskin, The New York Review of Books, 21 Apr. 2022 Combine pleiotropy, the effect of one gene on multiple traits, with polygeny and epistasis, and the tangle of abstraction gets intractable very quickly. Razib Khan, Discover Magazine, 19 Jan. 2011

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pleiotropy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1921, in the meaning defined above

Time Traveler
The first known use of pleiotropy was in 1921

Dictionary Entries Near pleiotropy

Cite this Entry

“Pleiotropy.” Dictionary, Merriam-Webster, Accessed 30 Mar. 2023.

Medical Definition


plei·​ot·​ro·​py plī-ˈä-trə-pē How to pronounce pleiotropy (audio)
plural pleiotropies
: the quality or state of being pleiotropic
Last Updated: - Updated example sentences
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