Pronunciation: [θɹɪˈə͡ʊz njuːklˈɪɪk ˈasɪd] (IPA) 
The spelling of "threose nucleic acid" is based on its chemical structure. Its name comes from the three-carbon sugar, threose, which makes up a part of its backbone. The word "nucleic" relates to its composition of nucleotides and the word "acid" indicates its acidic properties. It is pronounced /ˈθriː.oʊs ˌnuːkli.ɪk ˈæsɪd/ or "three-ohs new-klee-ik ass-id". This complex name is often abbreviated as TNA.
Threose nucleic acid (TNA) is a synthetic molecule that serves as an alternative to deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) as an information-carrying nucleic acid. TNA differs from DNA and RNA in its sugar component, as it utilizes a threose sugar rather than ribose or deoxyribose.
The backbone of TNA consists of repeating threose sugar units linked together via phosphodiester bonds. Like DNA and RNA, TNA also contains nucleobases connected to the sugar units. The nucleobases in TNA include adenine (A), cytosine (C), guanine (G), and thymine (T), which form complementary base pairs. However, in TNA, thymine is sometimes replaced by uracil (U).
TNA holds promise in the field of synthetic biology and molecular evolution due to its potential ability to store genetic information, as well as its potential for catalytic activity. It has been suggested that TNA might have played a role in the early stages of chemical evolution before the dominance of DNA and RNA.
Although TNA is not naturally occurring, it has been created and modified in laboratory settings. Ongoing research aims to explore the properties and potential applications of TNA, such as its potential use in the development of novel therapeutic agents or as a tool for studying fundamental biological processes.
