The complete set of nucleobases found in terrestrial DNA and RNA — adenine, guanine, cytosine, thymine and uracil — have been detected in samples returned from the asteroid Ryugu, according to research published in Nature Astronomy. The findings offer new insights into the early Solar System's chemistry.
Nucleobases are essential components of DNA and RNA, which underpin life on Earth. Detecting them in uncontaminated extraterrestrial material helps researchers to understand how such compounds can form in the absence of life and be transported across the Solar System. Previous analyses of Ryugu have reported the presence of uracil, whereas samples from meteorites and the near-Earth asteroid Bennu have revealed a wider diversity.
Toshiki Koga and colleagues analysed two Ryugu samples collected by the Hayabusa 2 mission and detected all five canonical nucleobases — adenine, guanine, cytosine, thymine, and uracil — in both samples. They compared the results with those obtained from the Murchison and Orgueil meteorites and with the returned samples from the asteroid Bennu. They found significant differences in the relative abundances of the nucleobases. More specifically, Ryugu contains roughly comparable amounts of purine nucleobases (adenine and guanine) and pyrimidine nucleobases (cytosine, thymine and uracil), while Murchison has more purine nucleobases while samples from Bennu and Orgeuil are richer in pyrimidine nucleobases. These results reflect the different chemical, environmental, and evolutionary histories of their respective parent bodies.
The detection of these nucleobases in asteroid and meteorite materials, despite their chemical differences, implies that they are widespread throughout the Solar System. The findings also suggest that carbonaceous asteroids may have contributed to the chemical inventory of early Earth, the authors conclude.
Article details
A complete set of canonical nucleobases in the carbonaceous asteroid (162173) Ryugu
DOI
https://doi.org/10.1038/s41550-026-02791-z
Corresponding Author:
Toshiki Koga
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
Email: [email protected]
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