Some of life’s key building blocks — known as nitriles — have been discovered by scientists at the heart of our Milky Way galaxy.
They were spotted in a molecular cloud of gas and dust by a team of international researchers using two telescopes in Spain.
Nitriles are important building blocks for RNA – a DNA-like nucleic acid that is present in all living cells.
Experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, providing support for the “RNA World” theory of the origin of life.
This suggests that life on Earth was originally based only on RNA and that DNA and protein enzymes evolved later.
RNA can perform both functions: to store and copy information such as DNA, and to catalyze reactions such as enzymes.
According to the ‘RNA World’ theory, nitriles and other building blocks for life do not necessarily all have to have originated on Earth itself.
Discovery: Some of life’s key building blocks — known as nitriles — have been discovered by scientists at the heart of our Milky Way galaxy. They were spotted in a molecular cloud of gas and dust (similar to the one in the picture) by a team of international researchers

Experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, providing support for the “RNA World” theory of the origin of life. This suggests that nitriles may have originated in space and ‘lifted up’ to young Earth in meteorites and comets (stock image)
They may also have originated in space and ‘lifted’ to young Earth in meteorites and comets during the ‘Late Heavy Bombardment’ period, between 4.1 and 3.8 billion years ago.
In support, nitriles and other precursor molecules to nucleotides, lipids and amino acids have been found in recent comets and meteors.
The question is, where in space could these molecules come from?
Primary 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 is about three light-years across, with a mass 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 evolve into a stellar nursery in the future.
The team of experts discovered a range of nitriles, including cyanosole, propargyl cyanide, cyanopropyne and possibly cyanoformaldehyde and glycolonitrile, none of which had previously been found in the cloud, known as G+0.693-0.027.
Lead study author Dr. Víctor M. Rivilla, a researcher at the Center for Astrobiology of the Spanish National Research Council, said: ‘Here we show that the chemistry taking place in the interstellar medium is able to efficiently form multiple nitriles, which are essential molecular precursors to the ‘RNA World’ scenario.’
He added: ‘The chemical content of G+0.693-0.027 is comparable to that of other star-forming regions in our galaxy, as well as to solar system objects such as comets.
“This means his research could give us important insights into the chemical ingredients that were available in the nebula that gave rise to our planetary system.”
Researchers used the 30-meter-wide IRAM Granada Telescope and the 40-meter-wide Yebes Telescope in Guadalajara.
The team of experts discovered a range of nitriles, including cyanosole, propargyl cyanide and cyanopropyne, which had not yet been found in G+0.693-0.027, although they had been reported in 2019 in the TMC-1 dark cloud in the constellations Taurus and Auriga, a molecular weight cloud with very different conditions than G+0.693-0.027.
The scientists also found possible evidence of cyanoformaldehyde and glycolonitrile.
Cyanoformaldehyde was first detected in the molecular clouds TMC-1 and Sgr B2 in the constellation Sagittarius, and glycolonitrile in the sun-like protostar IRAS16293-2422 B in the constellation Ophiuchus.

Two types of chemical building blocks – or nucleobases – are required for the formation of DNA and RNA
Fellow researcher Dr Miguel A Requena-Torres, a lecturer at Towson University in Maryland, said: “Thanks to our observations over the past few years, including the current results, we now know that nitriles are among the most abundant chemical families in the universe.
“We’ve found them in molecular clouds at the center of our galaxy, protostars of various masses, meteorites and comets, as well as in the atmosphere of Titan, Saturn’s largest moon.”
Author Dr Izaskun Jiménez-Serra, also a researcher at the Center for Astrobiology of the Spanish National Research Council, said: ‘We have so far discovered several simple precursors of ribonucleotides, the building blocks of RNA.
‘But there are still important missing molecules that are difficult to detect.
‘We know, for example, that life on Earth probably also required other molecules, such as lipids, which are responsible for the formation of the first cells.
“Therefore, we also need to focus on understanding how lipids can be formed from simpler precursors available in the interstellar medium.”
The study is published in the journal Frontiers.
†