Editing Messenger RNA (section)

===Uracil substitution for thymine===
mRNA uses uracil (U) instead of thymine (T) in DNA. uracil (U) is the complementary base to adenine (A) during transcription instead of thymine (T). Thus, when using a template strand of DNA to build RNA, thymine is replaced with uracil. This substitution allows the mRNA to carry the appropriate genetic information from DNA to the ribosome for translation. Regarding the natural history, uracil came first then thymine; evidence suggests that RNA came before DNA in evolution.<ref>{{Cite web |title=The Information in DNA Is Decoded by Transcription {{!}} Learn Science at Scitable |url=http://www.nature.com/scitable/topicpage/the-information-in-dna-is-decoded-by-6524808 |access-date=2024-05-03 |website=www.nature.com |language=en}}</ref> The [[RNA World]] hypothesis proposes that life began with RNA molecules, before the emergence of DNA genomes and coded proteins. In DNA, the evolutionary substitution of thymine for uracil may have increased DNA stability and improved the efficiency of DNA replication.<ref>{{Cite web |title=RNA world (article) {{!}} Natural selection |url=https://www.khanacademy.org/science/ap-biology/natural-selection/origins-of-life-on-earth/a/rna-world |access-date=2024-05-03 |website=Khan Academy |language=en}}</ref><ref>{{Cite web |title=The presence of thymine the place of uracil also confers additional stability to DNA. How? |url=https://www.toppr.com/ask/question/the-presence-of-thymine-at-the-place-of-uracil-also-confers-additional-stability-to-dna/ |access-date=2024-05-04 |website=Toppr Ask |language=en}}</ref>