Building blocks of RNA discovered at the center of the Milky Way

A faint red molecular cloud in the Milky Way.

A team of researchers say they’ve found some building blocks of RNA in a molecular cloud near the center of the Milky Way. The discovery has implications for theories about how life began on Earth – and perhaps elsewhere.

The molecular cloud is called G+0.693-0.027. The team of astrophysicists, astrobiologists and chemists used two telescopes in Spain to study the cloud to unravel details of its chemistry.

Ribonucleic acid (RNA) is a molecule that is present in all living cells and behaves similarly to DNA, although it is single-stranded. There is proof that RNA may have preceded DNA based on laboratory observations of ribosomes composed of RNA.

Whether ancient RNA could have boosted life or not is another matter. thThe latest team found several organic molecules in the cloud that are part of a group called nitriles that may have been important in generating RNA in the early universe; The team’s results were released today in limits in astronomy and space sciences.

“Here we show that the chemistry occurring in the interstellar medium is able to efficiently form multiple nitriles, which are important molecular precursors of the ‘RNA World’ scenario,” said Víctor Rivilla, astrobiologist at the National Institute of Aerospace Technology in Madrid, in a border publication.

That RNA world hypothesis postulated that RNA with genetic and metabolic activity was fundamental to the origins of life. A few studies in the 1990s showed that RNA could have accelerated life as we know it because it could do genetic work like DNA but catalyze reactions like proteins. There are also problems with the theorybut it’s still interesting to think about.

“There are still important missing molecules that are difficult to discover,” said Izaskun Jiménez-Serra, an astrophysicist also at the National Institute of Aerospace Technology, in the same press release. “We know, for example, that other molecules such as lipids, which are responsible for the formation of the first cells, were probably also required for the emergence of life on Earth. Therefore, we should also focus on understanding how lipids can be formed from simpler precursors available in the interstellar medium.”

The earliest evidence of life on Earth is 3.5-billion-year-old stromatolites, sedimentary concretions created by ancient bacteria as they grew. If there is fossilized life on Mars, the best guess is that it is likely looks something like this.

But before stromatolites, something was needed to seed life after the earth formed. One theory holds that all the ingredients needed for life arrived on Earth about 4 billion years ago (give or take several hundred million years), in a period called the Late Heavy Bombardment.

During the bombardment, the Earth and Moon were struck by asteroids and comets, evidence of which is now seared into the planet’s crust (and the Moon’s surface). It’s possible that nitriles like those found by the recent team may have arrived on some of these ancient asteroids as well liquid water is said to have reached our planet.

Nitriles have also been found in various protostars, meteorites, and even in Titan’s atmosphere. Saturn’s largest moon. It is a reminder that we are in a great cosmic soup that has been stirring for billions of years – ingredients floating around everywhere.

“The chemical content of G+0.693-0.027 is similar to that of other star-forming regions in our galaxy, as well as that of Solar System objects such as comets,” Rivilla said. “This means that his study can provide us with important insights into the chemical components that were available in the nebula that gave rise to our planetary system.”

Rome wasn’t built in a day, and neither was life on earth. However life arose, it required things like RNA to get going. Where this RNA came from remains a mystery, but the fact that its building blocks can be found even near the center of the Milky Way suggests that organic molecules are common in our galaxy. Whether that means life is too…well, scientists just have to keep looking.

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