A
new study conducted by scientists at the Institute for Advanced Study, the
Earth-Life Science Institute (ELSI), and the University of New South Wales marks
an important step forward in the effort to understand the chemical origins of
life. The findings of this study demonstrate how "continuous reaction
networks" are capable of producing RNA precursors and possibly ultimately
RNA itself -- a critical bridge to life.
To
conduct this work, the team exposed a mixture of very simple small molecules --
common table salt, ammonia, phosphate, and hydrogen cyanide -- to a high energy
gamma radiation source. These conditions simulate radioactive environments made
possible by naturally occurring radioactive minerals, which were likely much
more prevalent on early Earth. The team also allowed the reactions to
intermittently dry out, simulating evaporation in shallow puddles and beaches.
These experiments returned a variety of compounds that may have been important
for the origins of life, including precursors to amino acids and other small
compounds known to be useful for producing RNA.
The
authors use the term "continuous
reaction network"
to describe an environment in which intermediates are not purified, side
products are not removed, and no new reagents are added after the initial
starting materials. In other words, the synthesis of molecules occurs in a
dynamic environment in which widely varied compounds are continuously being
formed and destroyed, and these products react with each other to form new
compounds.
Future
work will focus on mapping out reaction pathways for other chemical substances
and testing whether further cycles of radiolysis followed by dry-down can
generate higher order chemical products.
See:
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)
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