Found an important component of the origin of life on the asteroid Ryugu

Scientists are now actively investigating samples from the Ryugu asteroid returned to Earth by the Japanese spacecraft Hayabusa-2. In recent studies, an important building block of life was found in samples — uracil. The discovery was reported by a team of Japanese astrochemists on March 21 in the publication Nature Communications.

Ryugu asteroid. Photo: JAXA

“The detection of uracil in the Ryugu sample is very important to clearly demonstrate that it is indeed present in an extraterrestrial environment,” explains astrochemist Yasuhiro Oba from Hokkaido University in Sapporo, Japan. 

Great discovery of 10 mg samples

Yasuhiro’s team received about 10 mg of Ryugu samples for analysis. As a result, the researchers weren’t sure they would be able to detect any building blocks at all. Although earlier they could find uracil in other meteorites.

The Japanese spacecraft Hayabusa-2 collected these samples from the Ryugu asteroid during two separate approaches. The sample on the left contains 38.4 mg of material, and on the right — 37.5 mg. Analysis of approximately 10 mg of samples provided to the team revealed the presence of uracil, the main building block of life. Photo: JAXA

Uracil has previously been found in meteorite samples, including a rare class called CI-chondrites, which contain large amounts of organic compounds. But these meteorites fell to Earth and were polluted by the planet’s environment, so they could not be a source for searching for the bricks of life.

Why is uracil so important?

Ryugu samples were collected in space. Therefore, they are the purest fragments of the Solar System that are available to scientists today. This means that the team can exclude the influence of terrestrial biology. Scientists used hot water to isolate organic material from Ryugu samples. Then — a special acid for breaking chemical bonds and separating uracil and other smaller molecules.

The surface of the Ryugu asteroid from Hayabusa-2

Uracil is one of the building blocks forming the RNA structure necessary for the creation of protein in all living cells. One theory of the origin of life suggests that RNA predates DNA and proteins, and that ancient organisms relied on RNA for chemical reactions related to life. 

Earlier, scientists showed how RNA could be formed on Mars and on Earth.

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