Scientists analyzing pristine samples from the asteroid Ryugu have identified all five nucleobases essential to DNA and RNA, according to findings published this week. The discovery marks the first time the complete set of genetic building blocks—adenine, guanine, cytosine, thymine, and uracil—has been detected together in material returned from a carbon-rich asteroid. Ryugu, a near-Earth object roughly 4.5 billion years old, was sampled by Japan's Hayabusa2 mission, which delivered subsurface material to Earth in 2020. Researchers said the samples were shielded from terrestrial contamination, strengthening the case that the molecules formed in space rather than arriving after landing.
The finding adds to mounting evidence from other asteroids and meteorites that these prebiotic molecules were widespread throughout the early Solar System. Scientists caution that the presence of nucleobases alone does not constitute evidence of life, but the results suggest the raw ingredients necessary for genetic information storage were available on ancient planetary bodies. The research, which has not yet undergone full peer review, may inform future missions and laboratory studies on the origins of life. Independent experts described the work as significant while noting that further analysis is needed to confirm the extraterrestrial origin of each compound.
Independent reporting synthesized from primary wires and global correspondents.