Some of life’s key building blocks, known as nitriles, have been discovered by scientists in the very heart of our Milky Way galaxy.
They were discovered in a molecular cloud of gas and dust by a group of international researchers using two telescopes in Spain.
Nitriles are essential building blocks for RNA, a DNA-like nucleic acid found in all living cells.
The experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, supporting the “RNA World” theory of the origin of life.
This suggests that life on Earth was originally based only on RNA, while DNA and protein enzymes evolved later.
RNA can perform both of its functions: storing and copying information, like DNA, and catalyzing reactions, like enzymes.
According to the RNA World theory, nitriles and other building blocks for life do not have to originate on Earth itself.
Discovery: Some of life’s key building blocks, known as nitriles, have been discovered by scientists in the heart of our Milky Way galaxy. They were discovered in a molecular cloud of gas and dust (similar to this one in the photo) by a group of international researchers.
The experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, supporting the “RNA World” theory of the origin of life. This suggests that nitriles could originate in space and hitchhike to the young Earth inside meteorites and comets (archive image).
They may also have originated in space and hitchhiked to the young Earth inside meteorites and comets during the Late Heavy Bombardment, between 4.1 and 3.8 billion years ago.
In support of this, nitriles and other precursor molecules of nucleotides, lipids, and amino acids have been found inside recent comets and meteors.
The question is, where in space could these molecules come from?
The first candidates are molecular clouds, which are dense and cold regions of the interstellar medium and are suitable for the formation of complex molecules.
For example, the molecular cloud G + 0.693-0.027 has a temperature of about 100 K and a diameter of about three light years, and its mass is about a thousand times that of our Sun.
There is no evidence that stars are currently forming within G+0.693-0.027, although scientists suspect it could become a stellar nursery in the future.
The panel of experts found a number of nitriles, including cyanoallene, propargyl cyanide, cyanopropine, and possibly cyanoformaldehyde and glycolonitrile, none of which had previously been detected in the cloud known as G+0.693-0.027.
Study lead author Dr. Victor M. Rivilla, research fellow at the Center for Astrobiology at the Spanish National Research Council, said: “Here we show that the chemistry that takes place in the interstellar medium is able to efficiently form multiple nitriles, which are key molecular precursors of the ‘RNA World’ scenario.
He added: “The chemical composition of G+0.693-0.027 is similar to that of other star-forming regions in our galaxy, as well as solar system objects such as comets.
“This means that studying it could give us important information about the chemical ingredients that were available in the nebula that gave rise to our planetary system.”
The researchers used the 100-foot (30 m) wide IRAM telescope in Granada and the 130-foot (40 m) wide Yebes telescope in Guadalajara.
The panel of experts found a number of nitriles, including cyanoallene, propargyl cyanide, and cyanopropine, which have not yet been detected in G+0.693–0.027, although they were reported in 2019 in the dark cloud TMC-1 in the constellations of Taurus and Taurus. Aurigae, a molecular cloud with very different conditions than G+0.693-0.027.
The scientists also found possible evidence for the presence of cyanoformaldehyde and glycolonitrile.
Cyanoformaldehyde was first detected in the molecular clouds TMC-1 and Sgr B2 in the constellation Sagittarius, and glycolonitrile was first detected in the sun-like protostar IRAS16293-2422 B in the constellation Ophiuchus.
Two types of chemical building blocks, or nucleobases, are needed to form DNA and RNA.
Study co-author Dr. Miguel A. Requena-Torres, professor at Towson University in Maryland, said: “Thanks to our observations over the past few years, including the present results, we now know that nitriles are one of the most common chemical families in the world. Universe.
“We found them in molecular clouds at the center of our galaxy, protostars of various masses, meteorites and comets, and in the atmosphere of Titan, Saturn’s largest moon.”
The author, Dr. Isacun Jiménez-Serra, also a researcher at the Center for Astrobiology at the Spanish National Research Council, said: “So far, we have discovered several simple precursors of ribonucleotides, the building blocks of RNA.
“But there are still key missing molecules that are difficult to detect.
“For example, we know that the origin of life on Earth probably also required other molecules, such as lipids, which are responsible for the formation of the first cells.
“Therefore, we should also focus on understanding how lipids can form from the simpler precursors available in the interstellar medium.”
Research published in the journal Borders.
