cy·​to·​sine | \ ˈsī-tə-ˌsēn How to pronounce cytosine (audio) \

Definition of cytosine

: a pyrimidine base C4H5N3O that codes genetic information in the polynucleotide chain of DNA or RNA — compare adenine, guanine, thymine, uracil

Examples of cytosine in a Sentence

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Her team reported last year in Cell that many mRNA cytosine bases are acetylated. Ken Garber, Science | AAAS, "Hidden layer of gene control influences everything from cancer to memory," 1 July 2019 In a process called hydrolytic deamination, for example, the base cytosine spontaneously loses its amino group and becomes uracil. Quanta Magazine, "Ancient DNA Yields Snapshots of Vanished Ecosystems," 29 May 2019 In 1953, scientists proposed that DNA is structured as a double helix, with the chemical bases—adenine (A), cytosine (C), guanine (G), and thymine (T)—stacked up in pairs between two intertwining lengths of sugar and phosphate. Ryan Rossotto, National Geographic, "DNA, explained," 12 June 2019 For instance, with height, having a guanine base instead of a cytosine one in a particular DNA region might correlate with being 0.1 millimeter taller than average. Quanta Magazine, "New Turmoil Over Predicting the Effects of Genes," 23 Apr. 2019 To form the i-motif, the double helix untwists and then one of the strands bunches up with a bunch of cytosine molecules. Avery Thompson, Popular Mechanics, "Scientists Discover That the Double Helix Isn't the Only DNA Form," 24 Apr. 2018 Tobacco Doctors already knew that tobacco could cause cancer, but Alexandrov’s work showed how—by preferentially mutating certain bases (such as cytosine) into others (adenine). Jacqueline Detwiler, Popular Mechanics, "One Guy With a Supercomputer Who's Chasing the Causes of Cancer," 19 Mar. 2018 The bases are often referred to as A, C, G and T, the initials of their full chemical names, adenine, cytosine, guanine and thymine. The Economist, "BiotechnologyGene editing takes another step forward," 26 Oct. 2017 The nascent technology converts the 1s and 0s of computing’s binary code into A, C, G and T, the letters that correspond to DNA base types, adenine, cytosine, guanine and thymine. Jay Greene, WSJ, "Malware Stored in Synthetic DNA Can Take Over a PC, Researchers Find," 10 Aug. 2017

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

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First Known Use of cytosine

1894, in the meaning defined above

History and Etymology for cytosine

International Scientific Vocabulary cyt- + -ose + -ine entry 2

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Last Updated

9 Jul 2019

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Time Traveler for cytosine

The first known use of cytosine was in 1894

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cy·​to·​sine | \ ˈsīt-ə-ˌsēn How to pronounce cytosine (audio) \

Medical Definition of cytosine

: a pyrimidine base C4H5N3O that codes genetic information in the polynucleotide chain of DNA or RNA — compare adenine, guanine, thymine, uracil

More from Merriam-Webster on cytosine Encyclopedia article about cytosine

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an act or instance of editing or removing

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