A team of Japanese scientists has confirmed that all five nucleobases that form the genetic code of life on Earth are present in samples from the asteroid Ryugu, collected by JAXA's Hayabusa2 mission in 2020. The finding, published in Nature Astronomy, supports the idea that the molecular ingredients of life were forming in space billions of years ago and may have been delivered to the early Earth by asteroids.
The researchers analysed two samples of material from Ryugu under ultra-clean laboratory conditions, extracting organic molecules with water and hydrochloric acid. They found roughly similar amounts of each of the five nucleobases: adenine, guanine, cytosine, thymine and uracil.
In 2023, an international team had reported finding uracil in Ryugu, but the new study confirms the presence of all five. Pristine asteroid samples like Ryugu, collected directly in space, are protected from Earth's contamination that can affect meteorites that fall to Earth.
Previous studies of meteorites that landed on Earth (the Murchison meteorite in Australia in 1969 and the Orgueil meteorite in France in 1864) have also yielded a rich variety of organic molecules, including nucleobases. In 2025, samples from NASA's mission to asteroid Bennu also contained all five nucleobases. The chemical composition varies between asteroids: Murchison is enriched in purines, while Bennu and Orgueil contain more pyrimidines, a balance that may be influenced by ammonia.
The results indicate that carbon-rich asteroids throughout the Solar System contain diverse prebiotic chemistry, and that the exact mixture depends on each asteroid's chemical environment and history. The discovery on Ryugu, a remnant of the early Solar System whose materials can be preserved largely unchanged for about 4.5 billion years, suggests the ingredients for life may have been widespread in the early Solar System, connecting the origin of life to a larger cosmic chemical story.
Analysis
Why This Matters
- The presence of all five nucleobases on a pristine asteroid strengthens the theory that life's building blocks formed in space and were delivered to Earth.
- It shows that the chemical ingredients for DNA and RNA are not unique to Earth and may be common across the Solar System.
- The results help scientists understand the chemical conditions and processes that led to the origin of life.
Background
Nucleobases are nitrogen-containing organic molecules that form the letters of DNA and RNA. The five main nucleobases are adenine, guanine, cytosine, thymine and uracil. They combine with sugars and phosphates to form nucleotides, the building blocks of genetic material. The Ryugu samples were returned to Earth by Japan's Hayabusa2 mission in 2020. Previous research had detected uracil in Ryugu, and later all five in Bennu samples. The new study provides further confirmation of widespread nucleobase formation in the early Solar System.
What to Watch
- Analysis of samples from other asteroids and comets, such as those planned for future missions, to see if the pattern holds.
- Further studies on the chemical differences between asteroids to understand the role of ammonia and other factors.
- Investigation into whether other complex organic molecules, such as amino acids or sugars, are similarly abundant in pristine asteroid material.
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12 claims in this story checked against 1 source: 12 supported.
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- SupportedAll five DNA and RNA nucleobases have been found in Ryugu samples.Latest Science News -- ScienceDaily: “A new study reveals all five fundamental nucleobases – the molecular “letters” of life – have been detected in samples from the asteroid Ryugu.”
- SupportedA Japanese study confirms that pristine Ryugu material contains molecular ingredients of life.Latest Science News -- ScienceDaily: “Now, in a study published in Nature Astronomy, a team of Japanese scientists has confirmed all five nucleobases are present in this pristine asteroid material.”
- SupportedThe Ryugu samples were returned in 2020 by JAXA’s Hayabusa2 mission.Latest Science News -- ScienceDaily: “The Ryugu samples were returned from space in 2020 by Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 mission.”
- SupportedThe study was published in Nature Astronomy.Latest Science News -- ScienceDaily: “Now, in a study published in Nature Astronomy, a team of Japanese scientists has confirmed all five nucleobases are present in this pristine asteroid material.”
- SupportedThe findings support the idea that life’s molecular ingredients may have formed in space billions of years ago and may have been delivered to early Earth by asteroids.Latest Science News -- ScienceDaily: “The discovery of all five nucleobases on Ryugu suggests the molecular ingredients of life may have been already forming in space billions of years ago. Asteroids may have helped deliver those ingredients to the early Earth”
- SupportedResearchers analysed two Ryugu samples under ultra-clean conditions, extracting organic molecules with water and hydrochloric acid.Latest Science News -- ScienceDaily: “Researchers have to use ultra-clean lab conditions to avoid contaminating it. They extracted organic molecules using water and hydrocholoric acid, and then purified them for further detection.”
- SupportedThe researchers found roughly similar amounts of adenine, guanine, cytosine, thymine and uracil in the two samples.Latest Science News -- ScienceDaily: “They found all five nucleobases in the two Ryugu samples they analysed, in roughly similar amounts.”
- SupportedAn international team reported finding uracil in Ryugu in 2023, and the new study confirms all five nucleobases.Latest Science News -- ScienceDaily: “In 2023, an international team reported they had found one of the nucleobases in these samples – uracil. Now, in a study published in Nature Astronomy, a team of Japanese scientists has confirmed all five nucleobases are present in this pristine asteroid material.”
- SupportedRyugu samples collected directly in space are protected from Earth contamination that can affect meteorites that land on Earth.Latest Science News -- ScienceDaily: “Because the Ryugu samples were collected directly in space and protected from Earth’s contamination, they provide one of the clearest views of ancient Solar System chemistry.”
- SupportedThe Murchison meteorite fell in Australia in 1969 and the Orgueil meteorite is from France in 1864; both have yielded organic molecules, including nucleobases.Latest Science News -- ScienceDaily: “The Murchison meteorite that fell in Australia in 1969 , and the Orgueil meteorite in France, 1864 , have previously yielded a rich variety of organic molecules, including nucleobases.”
- SupportedBennu samples from a NASA mission contained all five nucleobases in 2025.Latest Science News -- ScienceDaily: “But pristine samples from NASA’s mission to asteroid Bennu also yielded all five nucleobases in 2025.”
- SupportedMurchison is enriched in purines, while Bennu and Orgueil contain more pyrimidines, and the balance may be influenced by ammonia.Latest Science News -- ScienceDaily: “Murchison is enriched in purines, while Bennu and Orgueil contain more pyrimidines. It is thought this balance may be influenced by ammonia, a key molecule that can shape which nucleobases can form.”