Threose nucleic acid 4476904 224370365 2008-07-08T15:39:22Z FghIJklm 4581470 Grammar '''[[Threose]] nucleic acid''' (TNA) is a [[polymer]] similar to [[DNA]] or [[RNA]] but differing in the composition of its "backbone". TNA is not known to occur in existing life on Earth. DNA and RNA have a [[deoxyribose]] and [[ribose]] sugar backbone, respectively, whereas TNA's backbone is composed of repeating [[threose]] units linked by [[phosphodiester bond]]s. The threose molecule is easier to assemble than ribose making it a possible precursor to RNA. DNA-TNA hybrid chains have been made in the laboratory using DNA polymerase. TNA can specifically base pair with RNA and DNA; this capability and chemical simplicity suggests that TNA could have preceded RNA as genetic material. ==See also== *[[Abiogenesis]] *[[Glycerol nucleic acid]] *[[Peptide nucleic acid]] ==External links== *[http://www.newscientist.com/article/mg17924052.500.html Was simple TNA the first nucleic acid on Earth to carry a genetic code?] - New scientist *[http://www.sciencemag.org/cgi/content/summary/290/5495/1306 ORIGIN OF LIFE: A Simpler Nucleic Acid] - [[Leslie Orgel]] ==References== * {{cite journal| title=A Simpler Nucleic Acid| last=Orgel| first=Leslie| journal=[[Science (journal)|Science]]| year=2000| month=Nov| pages=1306–1307| volume=290| issue=5495| doi=10.1126/science.290.5495.1306}} * {{cite journal| title=Modified nucleic acids on display| last=Watt| first=Gregory | journal=Nature Chemical Biology| year=2005| month=Feb| url=http://www.nature.com/nchembio/journal/vaop/nprelaunch/full/nchembio005.html| doi = 10.1038/nchembio005}} * {{cite journal| title=Chemical etiology of nucleic acid structure: the alpha-threofuranosyl-(3'->2') oligonucleotide system.| last=Schoning| first=K| coauthors=Scholz P; Guntha S; Wu X; Krishnamurthy R; Eschenmoser A| journal=[[Science (journal)|Science]]| year=2000| month=Nov| pmid = 11082060| doi=10.1126/science.290.5495.1347 }} {{Nucleic_acids}} {{genetics-stub}} [[Category:Nucleic acids]] [[Category:polymers]] [[it:Threose nucleic acid]] [[pl:TNA]] [[zh:蘇糖核酸]]