Samples returned by JAXA’s Hayabusa-2 mission from the C-type asteroid (162173) Ryugu contain all five canonical nucleobases -- purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil) -- pointing to a cosmic origin for some of life’s fundamental chemistry.

The study's lead author said that the presence of nucleobases "does not mean that life existed on Ryugu".