RNA Building Blocks Visible at the Center of the Milky Way

A team of researchers say they have found some of the building blocks of RNA in a molecular cloud close to 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 named G+0.693-0.027. A team of astrophysicists, astrobiologists and chemists conducted a cloud survey using two telescopes in Spain to uncover chemical details.

Ribonucleic acid (RNA) is a molecule present in all living cells that behaves similarly to DNA, although it is single-stranded. There is evidence that RNA could precede DNA, based on laboratory observations of ribosomes, which are composed of RNA.

However, whether ancient RNA could start life or not, is another matter. The team recently discovered several organic molecules in the cloud that are part of a group called nitriles, which may have been important in producing RNA in the early universe; The team’s results were published today in Frontiers in Astronomy and Space Sciences.

“Here we show that the chemistry occurring in the interstellar medium is capable of efficiently forming some nitriles, which are key molecular precursors of the ‘RNA World’ scenario,” said Víctor Rivilla, an astrobiologist at the National Institute of Aerospace Technology in Madrid, in the release. Frontiers.

The RNA world hypothesis states that RNA with genetic and metabolic activities is the basis of the origin of life. Several studies in the 1990s showed that RNA could start life as we know it, because it can do genetic work like DNA but can catalyze reactions like proteins. There’s also a problem with the theory, but it’s still interesting to consider.

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

The earliest evidence of life on Earth comes in the form of 3.5 billion-year-old stromatolites, concretions of sediment produced by ancient bacteria as they grew. If there is fossilized life on Mars, the best guess is it might look like that.

But before stromatolites, something was needed to breed life after Earth was formed. One theory is that whatever material needed for life arrived on Earth about 4 billion years ago (give or take a few hundred million years), in a period called the Late Heavy Bombardment.

During the bombardment, the Earth and Moon were hit by asteroids and comets, the evidence of which is now imprinted on the planet’s crust (and the Moon’s surface). It is possible that nitriles such as those discovered by the team recently arrived at some of those ancient asteroids, just as liquid water is proposed to reach our planet.

Nitriles have also been found in various protostars, meteorites, and even in the atmosphere of Titan, Saturn’s largest moon. It’s a reminder that we’re in a huge cosmic soup that’s been churned for billions of years — the ingredients are strewn everywhere.

“The chemistry of G+0.693-0.027 is similar to that of other star-forming regions in our galaxy, and also to solar system objects such as comets,” Rivilla said. “This means his research could provide us with important insights into the chemicals available in the nebula that gave rise to our planetary system.”

Rome was not built in a day, and neither was life on Earth. After all life did emerge, however, it required things like RNA to start. Where the RNA came from is still 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 scattered throughout our galaxy. Does that mean living too… well, scientists just need to keep looking around.

More: Scientists Find New Window Into Ancient Earth Hell

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