: a purine base C5H5N5O that codes genetic information in the polynucleotide chain of DNA or RNA compare adenine, cytosine, thymine, uracil
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Scientists have discovered that a sample of the Ryugu asteroid collected by Japan's Hayabusa 2 spacecraft contains the nucleobases adenine, guanine, cytosine, thymine and uracil, the building blocks of DNA and RNA upon which all life is based.—Robert Lea, Space.com, 17 Mar. 2026 Temozolomide—the standard of care for glioblastoma—works by depositing a methyl group onto the DNA of cells, specifically on guanine, one of DNA’s four base molecules.—Isabella Backman, Hartford Courant, 27 Jan. 2026 Those rungs are made up of pairs of four different chemical building blocks, called bases — adenine, thymine, cytosine and guanine (A,T,C and G).—F.d. Flam, Mercury News, 26 Nov. 2025 Adenine always pairs with thymine, and guanine always pairs with cytosine.—IEEE Spectrum, 2 Oct. 2025 See All Example Sentences for guanine
Word History
Etymology
guano + -ine; from its being found especially in guano