Definition of "cytosine" []

• A pyrimidine base, C4H5N3O, that is the constituent of DNA and RNA involved in base pairing with guanine. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The position of the atoms in cytosine could be determined, because under the action of an oxidizing agent this substance breaks down into biuret and oxalic acid, and this elucidation of its constitution was soon followed by its synthesis."
• "DNA has four chemical bases - A, G, C and T - and ERV-9's DNA contains a lot of the C, or cytosine, which is easily chemically altered."
• "Epigenetic modifications, such as cytosine methylation, are inherited in plant species and may occur in response to biotic or abiotic stress, affecting gene expression without changing genome sequence."