A pyrimidine base, characteristically present in DNA, and absent from RNA. In DNA it pairs specifically with adenine in the complementary strand, so that the thymine:adenine base ratio is 1:1. Thymine is linked to other bases of the same strand through a sugar-phosphodiester backbone, the nucleotide of thymine being called thymidine (thymine + deoxyribose sugar + phosphate). Thymine is more fully described as 5-methyl-2,4-dioxypyrimidine and is derived from sugars and amino acids. Compare uracil. |
