Some of the key components of life, known as nitriles, have been detected by scientists at the heart of our Milky Way galaxy.
They were detected in a molecular cloud of gas and dust by a team of international researchers using two telescopes in Spain.
Nitriles are important components for RNA, a DNA-like nucleic acid present in all living cells.
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 solely on RNA, and that DNA and protein enzymes evolved later.
RNA can perform both functions: storing and copying information such as DNA and catalyzing reactions such as enzymes.
According to the “RNA World” theory, nitriles and other building blocks of life did not necessarily arise on Earth itself.
Discovery: Some of the key components of life, known as nitriles, have been detected by scientists at the heart of our Milky Way galaxy. They were detected in a molecular cloud of gas and dust (similar to the one shown in the photo) by a team of international researchers
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 may have originated in space and “hitchhiked” the young Earth into meteorites and comets (stock image)
LIFE ON EARTH MAY HAVE BEGUN THANKS TO A MODIFIED VERSION OF MODERN RNA
Life on Earth could have started thanks to a modified version of the sister molecule of current DNA, scientists believe.
DNA is the backbone of life and almost our entire planet depends on it, but on primordial Earth, a primitive version of its lesser-known sister, RNA, was the focal point of evolution. experts say.
RNA is structurally similar to DNA, except that one of the four fundamental pieces, thymine, is replaced by uracil.
This changes the shape and structure of the molecule and researchers have long believed that this chemical was vital for the development of the first life forms on Earth.
An accidental discovery by Harvard academics published in December 2018 found that a slightly different version of RNA may have been the key ingredient that allowed life on Earth to flourish.
Scientists claim that a chemical called inosine could have been present instead of guanine, allowing the development of life.
This slight change in the bases, known as nucleotides, may provide the first known proof of the “global RNA hypothesis,” a theory that states that RNA was integral to primitive life forms – they say.
They could also have originated in space and “hitchhiked” the young Earth within meteorites and comets during the period of the “late heavy bombardment” between 4,100 and 3,800 million years ago.
In support, nitriles and other nucleotide, lipid, and amino acid precursor molecules have been found within recent comets and meteors.
The question is, where could these molecules have come into space?
The main candidates are molecular clouds, which are dense, 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 in diameter, 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 to become a stellar nursery in the future.
The team of experts detected a number of nitriles including cyanoallene, propargyl cyanide, cyanopropy and possibly cyanoformaldehyde and glycolinitrile, none of which had previously been found in the cloud, known as G + 0.693-0.027.
The lead author of the study, Dr. Victor M. Rivilla, a researcher at the Center for Astrobiology of the Higher Council for Scientific Research, said: “Here we show that chemistry that takes place in the interstellar medium is capable of efficiently form multiple nitriles, which are key molecular molecular precursors of the “RNA World” scenario. ‘
He added: “The chemical content of G + 0.693-0.027 is similar to that of other star-forming regions of our galaxy, and also to that of objects in the solar system such as comets.
“This means that their study can give us important information about the chemical ingredients available in the nebula that give rise to our planetary system.”
The researchers used the 100-foot (30 m) wide IRAM Granada telescope and the 130-foot (40 m) wide Yebes telescope in Guadalajara.
The team of experts detected a number of nitriles such as cyanoallene, propargyl cyanide and cyanopropium, which had not yet been found at G + 0.693-0.027, although they had been reported in 2019 in the dark cloud. TMC-1 in the constellations of Taurus. and Auriga, a molecular cloud with very different conditions from G + 0.693-0.027.
Scientists also found possible evidence of cyanoformaldehyde and glycolinitrile.
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.
For DNA and RNA to form, two types of chemical building blocks (or nucleobases) are needed.
The study’s author, Dr. Miguel A Requena-Torres, a professor at Towson University in Maryland, said: “Thanks to our observations over the past few years, including current results, we now know that nitriles are are among the most abundant chemical families in the world.
“We found them in molecular clouds in the center of our galaxy, protostars of different masses, meteorites and comets, and also in the atmosphere of Titan, Saturn’s largest moon.”
The author, Dr. Izaskun Jiménez-Serra, also a researcher at the Center for Astrobiology of the Consejo Superior de Investigaciones Científicas, said: “So far we have detected several simple ribonucleotide precursors, the basic components of RNA.
“But there are still key molecules that are missing that are difficult to detect.
“For example, we know that the origin of life on Earth probably also required other molecules such as lipids, responsible for the formation of the first cells.
“Therefore, we should also focus on understanding how lipids could be formed from simpler precursors available in the interstellar medium.”
The study has been published in the journal Frontiers.
DNA AND RNA EXPLAINED: MOLECULES CONTAINING GENETIC INFORMATION FOR LIFE
DNA – deoxyribonucleic acid – is widely known as the molecule found in the nucleus of all our cells that contains genetic information.
It is shaped like a double helix and consists of small sections called nucleotides.
Each nucleotide contains a nucleobase, a sugar, and a phosphate group.
The sugar component of this particular molecule is called deoxyribose and constitutes the D of DNA.
It is a carbon-based cyclic chemical with five carbon atoms arranged like a pentagon.
In the second carbon atom is a singular hydrogen atom attached to deoxyribose.
This can also have additional oxygen attached.
In this case, the oxygenated chemical then forms what is known simply as ribose: the R of RNA.
The prefix deoxy literally means without oxygen.
Form of RNA and DNA
RIbose can do almost anything deoxyribose can and also encodes genetic information in some cells and organisms.
When oxygen is present, it drastically alters the way chemicals bind and sit next to other molecules.
When oxygen is present in RNA, it can take many forms.
When oxygen is not present at this specific location, in DNA, the molecule is formed as the iconic double helix.
Uses of RNA
DNA is often broken down into RNA and cells read to translate and transcribe the genetic code in order to make proteins and other molecules essential for life.
RNA uses three of the same base pairs as DNA: cytosine, guanine, and adenine.
The other base pair, thymine, is exchanged into RNA for uracil.
RNA is also often found in simpler organisms, such as bacteria.
It is often also a virus, with hepatitis, flu and HIV all forms of RNA.
Mitochondrial RNA
All animal cells use DNA, with one notable exception: mitochondria.
Mitochondria are central to the cell and convert glucose to pyruvate and then to adenosine triphosphate (ATP) through the Krebs cycle.
This whole process is done in this organelle of the cells and ATP is the universal form of energy and is used in all aerobic organisms.
In the mitochondria there is a small strand of RNA that is unique in the animal kingdom.
It is transmitted exclusively from the mother (the father lives in sperm but dissolves during fertilization) and allows humans to trace their maternal lineage over time.