Scientists have discovered a new chemical reaction involving benzene and hydrogen cyanide. It is so simple that it could explain the origin of nucleotides—the building blocks of DNA and RNA—on Earth. These are the foundation of organic life on our planet.
Building blocks of life
Researchers at the California Institute of Technology have discovered a new reaction involving benzene that could potentially explain how life originated on our planet. Specifically, it involves the formation of the building blocks of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
They serve as carriers of genetic information—a kind of instruction manual that guides the construction of proteins, cells, and the entire organism as a whole. At the same time, it has long been common knowledge that DNA and RNA are easily assembled from individual building blocks. The only problem is that these building blocks—adenine, guanine, cytosine, uracil, and thymine—had to have originated somehow as well.
Overall, scientists are already aware of dozens of processes that could potentially have led to the formation of RNA—the simplest form of matter capable of reproduction and evolution—from very simple organic compounds. However, every time they discover a new pathway, it becomes an important building block in the growing confidence that life could indeed have arisen naturally.
A new path
The new study began when researchers became curious about what organic compounds are actually contained within nucleotides. It turns out that these are mostly very simple molecules, such as nitrogen and methane. However, the most common structure found was benzene—a ring of six carbon atoms bonded to hydrogen atoms.
The scientists decided to test whether this molecule could have remained stable on Earth in ancient times, and the answer was yes. The next step was to find out what it could react with to form something significantly more complex, and they soon discovered a fairly simple answer.
Hydrogen cyanide (HCN) was widespread in the atmosphere of early Earth; it was stable and, as researchers have discovered, could easily react with benzene rings in the presence of light as a catalyst. This resulted in the formation of complex compounds that are precursors to nucleotides.
They are mostly water-soluble and could therefore easily have entered the oceans. There, they underwent reactions that supplied the necessary elements for their structure. The main advantage of this newly discovered pathway lies precisely in the fact that all the substances involved were very abundant, and the reaction was simple.
According to phys.org
