Scientists at  GNASA’s Goddard Space Flight Center have found trace amounts of three molecules related to DNA nucleobases adenine and guanine in samples of 12 carbon-rich meteorites, nine of which were recovered from Antarctica.

These nucleobase-related molecules, called nucleobase analogs, provide the first evidence that the compounds in the meteorites came from space and not terrestrial contamination.

The team analyzed an eight-kilogram (21.4-pound) sample of ice from Antarctica, where most of the meteorites in the study were found. The amounts of nucleobases found in the ice were much lower than in the meteorites.

More significantly, none of the nucleobase analogs were detected in the ice sample. The team also analyzed a soil sample collected near one of the non-Antarctic meteorite’s fall site. As with the ice sample, the soil sample had none of the nucleobase analog molecules present in the meteorite.

Ref.: Michael Callahan, paper to appear in PNAS [link]