A new analysis of samples from asteroid Ryugu found all five nucleobases used in DNA and RNA. The finding adds to evidence that some ingredients of genetic material occur in asteroids, but it does not show that life existed on Ryugu or explain how life began on Earth.
The study, published in Nature Astronomy, lists Toshiki Koga, Yasuhiro Oba, Yoshinori Takano, Hiroshi Naraoka, Nanako O. Ogawa, Kazunori Sasaki, Hajime Sato, Toshihiro Yoshimura and Naohiko Ohkouchi as authors. A report summarizing the work was provided to ScienceDaily by The Conversation; it identifies Kliti Grice, John Curtin Distinguished Professor of Organic and Isotope Geochemistry at Curtin University, as its original writer.
The five molecules are adenine and guanine, known as purines, and cytosine, thymine and uracil, known as pyrimidines. Nucleobases combine with sugars and phosphates to form nucleotides, the building blocks of genetic material. They are important ingredients in the chemistry of life, but finding them does not amount to finding genetic material, organisms or evidence of life.
The researchers detected all five in the two Ryugu samples they analyzed, in roughly similar amounts. Japan’s Hayabusa2 mission collected the material in space and returned it to Earth in 2020. The mission delivered 5.4 grams of asteroid material in total. Because the samples were collected directly in space, they offer a way to study asteroid chemistry with less risk of contamination from Earth than meteorites that have fallen and been recovered here.
The report says the researchers worked under ultra-clean laboratory conditions. They extracted organic molecules using water and hydrochloric acid, then purified them before detection. Those safeguards matter because even small amounts of terrestrial material could complicate the interpretation of compounds found in an asteroid sample.
The Ryugu result extends an earlier finding: an international team reported uracil in Ryugu samples in 2023. It also aligns with a 2025 report of all five nucleobases in pristine samples returned from asteroid Bennu. Meteorites such as Murchison, which fell in Australia in 1969, and Orgueil, which fell in France in 1864, have also yielded nucleobases among other organic molecules, though meteorites can be exposed to contamination during their journey to Earth and after landing.
The mix of compounds varies among these space rocks. The report says Murchison is enriched in purines, while Bennu and Orgueil contain more pyrimidines. Ammonia is thought to influence this balance, but the report does not establish a single explanation for the differences. The variation suggests that asteroids’ chemical histories and environments can shape which prebiotic molecules are present.
Taken together, the Ryugu and Bennu findings support the possibility that key components of genetic material formed in space and that asteroids may have delivered some of them to early Earth. That remains a possible contribution, not a demonstrated account of life’s origin. The reported result does not establish how much of these molecules reached Earth, whether they contributed to life’s emergence, or what other conditions would have been needed.
<a href="https://www.sciencedaily.com/releases/2026/11/261102075903.htm">Source: ScienceDaily report on the Ryugu finding</a>