Editing RNA world (section)

=== RNA-peptide coevolution ===
{{See also|RNP world}}
Another proposal is that the dual-molecule system we see today, where a nucleotide-based molecule is needed to synthesize protein, and a peptide-based (protein) molecule is needed to make nucleic acid polymers, represents the original form of life.<ref>{{cite journal | vauthors = Kunin V | title = A system of two polymerases--a model for the origin of life | journal = Origins of Life and Evolution of the Biosphere | volume = 30 | issue = 5 | pages = 459–466 | date = October 2000 | pmid = 11002892 | doi = 10.1023/A:1006672126867 | s2cid = 5616924 | bibcode = 2000OLEB...30..459K }}</ref> This theory is called RNA-peptide coevolution,<ref name="pascal">{{Citation | last = Pascal| first = Robert | contribution = A scenario starting from the first chemical building blocks| year = 2007 | title = From Suns to Life: A Chronological Approach to the History of Life on Earth | editor-last = Reisse | editor-first = Jacques | pages = 163–166 | publisher = Springer Science & Business Media | isbn = 978-0-387-45083-4}}</ref> or the Peptide-RNA world, and offers a possible explanation for the rapid evolution of high-quality replication in RNA (since proteins are catalysts), with the disadvantage of having to postulate the coincident formation of two complex molecules, an enzyme (from peptides) and a RNA (from nucleotides). In this Peptide-RNA World scenario, RNA would have contained the instructions for life, while peptides (simple protein enzymes) would have accelerated key chemical reactions to carry out those instructions.<ref name="Urzymes 2013">{{cite journal |title=Challenging Assumptions About the Origin of Life |journal=Astrobiology Magazine |date=18 September 2013 |url=http://www.astrobio.net/pressrelease/5692/challenging-assumptions-about-the-origin-of-life |access-date=2014-05-07 |url-status=usurped |archive-url=https://web.archive.org/web/20140508042711/http://www.astrobio.net/pressrelease/5692/challenging-assumptions-about-the-origin-of-life |archive-date=8 May 2014 }}</ref> The study leaves open the question of exactly how those primitive systems managed to replicate themselves — something neither the RNA World hypothesis nor the Peptide-RNA World theory can yet explain, unless [[polymerase]]s (enzymes that rapidly assemble the RNA molecule) played a role.<ref name="Urzymes 2013" />

A research project completed in March 2015 by the Sutherland group found that a network of reactions beginning with hydrogen cyanide and [[hydrogen sulfide]], in streams of water irradiated by UV light, could produce the chemical components of proteins and lipids, alongside those of RNA.<ref name="patel">{{cite journal | vauthors = Patel BH, Percivalle C, Ritson DJ, Duffy CD, Sutherland JD | title = Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism | journal = Nature Chemistry | volume = 7 | issue = 4 | pages = 301–307 | date = April 2015 | pmid = 25803468 | pmc = 4568310 | doi = 10.1038/nchem.2202 | bibcode = 2015NatCh...7..301P | author-link5 = John Sutherland (chemist) }}</ref><ref>{{cite news |last=Service |first=Robert F. |date=16 March 2015 |title=Researchers may have solved origin-of-life conundrum |url=https://www.science.org/content/article/researchers-may-have-solved-origin-life-conundrum |work=Science |type=News |location=Washington, D.C. |publisher=American Association for the Advancement of Science |issn=1095-9203 |access-date=2015-07-26 |url-status=live |archive-url=https://web.archive.org/web/20150812103559/http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |archive-date=12 August 2015 }}</ref> The researchers used the term "cyanosulfidic" to describe this network of reactions.<ref name="patel" /> In November 2017, a team at the [[Scripps Research Institute]] identified reactions involving the compound [[diamidophosphate]] which could have linked the chemical components into short peptide and lipid chains as well as short RNA-like chains of nucleotides.<ref>{{cite journal | vauthors = Gibard C, Bhowmik S, Karki M, Kim EK, Krishnamurthy R | title = Phosphorylation, oligomerization and self-assembly in water under potential prebiotic conditions | journal = Nature Chemistry | volume = 10 | issue = 2 | pages = 212–217 | date = February 2018 | pmid = 29359747 | pmc = 6295206 | doi = 10.1038/nchem.2878 }}</ref><ref>{{cite web|url=http://www.scripps.edu/news/press/2017/20171106krishnamurthy.html|title=Scientists Find Potential "Missing Link" in Chemistry That Led to Life on Earth|date=November 6, 2017|publisher=[[Scripps Research Institute]]|access-date=7 November 2017|url-status=live|archive-url=https://web.archive.org/web/20171107024003/http://www.scripps.edu/news/press/2017/20171106krishnamurthy.html|archive-date=7 November 2017}}</ref>