Thymine is one of the four Pyrimidines/nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T.
Uracil = 2,4-dioxy pyrimidine
Thymine = 2,4-dioxy-5-methyl pyrimidine
Cytosine = 2-oxy-4-amino pyrimidine
Orotic acid = 2,4-dioxy-6-carboxy pyrimidine
Cytosine is found in both DNA and RNA. Uracil is found only in RNA. Thymine is normally found in DNA. Sometimes tRNA will contain some thymine as well as uracil.
Thymine is also called 5-methyluracil or it may be represented by the capital letter "T" or by its three-letter abbreviation, Thy.
The molecule gets its name from its initial isolation from calf thymus glands by Albrecht Kossel and Albert Neumann in 1893. Thymine is found in both prokaryotic and eukaryotic cells, but it does not occur in RNA viruses.
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