All Five DNA and RNA Nucleobases Found on Asteroid Ryugu: "Building Blocks of Life Widely Present in the Solar System" [Reading Science]

Analysis of Samples Recovered Without Earth Contamination
Raises Possibility That Organic Molecules Were Supplied to Early Earth

All five nucleobases that make up the genetic information of terrestrial life forms were detected in samples brought from the asteroid Ryugu. The research team explained that this result should not be considered a 'discovery of life,' but rather as evidence suggesting that the building blocks of life may have been widely present throughout the solar system.

According to a study published in the international journal "Nature Astronomy" on March 17, a Japanese research team analyzed two samples from Ryugu, collected and returned to Earth by the Japan Aerospace Exploration Agency (JAXA) asteroid probe Hayabusa2. They identified all five standard nucleobases—adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)—which are the fundamental components of DNA and RNA.

Photo to aid understanding of the article. Spacecraft exploring an asteroid. Provided by NASA

This research is especially significant because it used samples that were recovered without any exposure to Earth's atmosphere or biological environment. Previously, studies on meteorites could not fully rule out the possibility of contamination from Earth's environment.

The research team also compared the nucleobase composition of the Ryugu samples with those in the carbonaceous meteorites Murchison and Orgueil, as well as samples from the asteroid Bennu collected by a US spacecraft. They found that each celestial body had a different nucleobase composition, which the researchers explained is evidence that each body underwent different chemical environments and evolutionary processes.

Moon Hongkyu, Principal Researcher at the Space Science Exploration Division of the Korea Astronomy and Space Science Institute, commented, "The confirmation of all five essential components of DNA and RNA in the asteroid samples is a major milestone, as it demonstrates that the building blocks corresponding to the blueprint of life also exist on asteroids."

He added, "Although nucleobases have previously been found in meteorites that fell to Earth, there have always been concerns about contamination from Earth's environment. This study is distinct in that it analyzed samples that were directly collected in space by a probe and returned in a sealed state."

Moon further stated, "The fact that different nucleobase ratios were observed in samples from Ryugu, Bennu, and Orgueil suggests that the pathways for organic molecule formation varied depending on the environment of the parent body. This indicates that the process of organic molecule formation in the early solar system was much more diverse and dynamic than previously thought."

Kang Sungjoo, Director at MoaScience and former Senior Researcher at the Korea Astronomy and Space Science Institute, said, "The core message of this study is not the discovery of life itself, but the possibility that the ingredients for life were widely distributed throughout the solar system. It is significant in that this has been directly verified using actual asteroid samples."

However, some point out that the detection of nucleobases does not immediately reveal the origin of life. Kang explained, "The formation of living organisms requires not only nucleobases, but also the formation of nucleotides—where sugars and phosphates are combined—as well as processes of self-replication and polymerization. Further experimental verification is needed regarding the pathways for nucleobase formation and their relationship with ammonia."

The researchers believe that future studies should include isotopic composition analysis of the nucleobases, comparative studies of various carbonaceous asteroids and meteorites, and experiments simulating actual small body environments.

Moon said, "Direct comparative research with samples collected from asteroid Bennu by the National Aeronautics and Space Administration (NASA) is expected to follow. Since Korea has already conducted basic research for near-Earth asteroid exploration and sample return missions, there is a possibility of participating in related research if policy support continues."

This content was produced with the assistance of AI translation services.