Ryugu Samples Show All Five Canonical Nucleobases, Pointing to Common Prebiotic Chemistry in the Solar System

Two Ryugu aggregates contain all five canonical nucleobases (adenine, guanine, cytosine, thymine, uracil) plus related N-heterocycles, supporting extraterrestrial delivery of basic life-building blocks. The study finds purine/pyrimidine ratios that correlate with ammonia levels and differ from Bennu, Orgueil, and Murchison, suggesting different parent-body chemistries but a shared formation pathway for nucleobases on primitive Solar System bodies and implications for Earth's prebiotic inventory.