Editing Cytosine (section)

== Theoretical aspects ==
Until October 2021, Cytosine had not been found in meteorites, which suggested the first strands of RNA and DNA had to look elsewhere to obtain this building block. Cytosine likely formed within some meteorite parent bodies, however did not persist within these bodies due to an effective [[deamination]] reaction into [[uracil]].<ref>{{Cite news|url=https://blogs.scientificamerican.com/guest-blog/did-the-seeds-of-life-come-from-space/|title=Did the Seeds of Life Come from Space?|last=Tasker|first=Elizabeth|newspaper=Scientific American Blog Network|access-date=2016-11-24}}</ref>

In October 2021, Cytosine was announced as having been found in meteorites by researchers in a joint Japan/NASA project, that used novel methods of detection which avoided damaging nucleotides as they were extracted from meteorites.<ref>{{cite journal |author1=Yasuhiro Oba |author2=Yoshinori Takano |author3=Yoshihiro Furukawa |author4=Toshiki Koga |author5=Daniel P. Glavin |author6=Jason P. Dworkin |author7=Hiroshi Naraoka |title=Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites |journal=Nature Communications |date=2022 |volume=13 |issue=1 |page=2008 |publisher=Nature.com |doi=10.1038/s41467-022-29612-x |pmid=35473908 |pmc=9042847 |bibcode=2022NatCo..13.2008O }}</ref>