NASA researchers have found convincing evidence that components of DNA can be made in space.
“People have been discovering components of DNA in meteorites since the 1960’s, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life,” said Dr. Michael Callahan of NASA’s Goddard Space Flight Center, according to NASA.
Now, new findings from analyzing 12 meteorites suggest that these molecules were actually created in space.
Apart from the nucleobases adenine and guanine, the researchers found in the meteorites purine, 2,6-diaminopurine, and 6,8-diaminopurine. These compounds are rarely found in terrestrial biology. They are called nucleobase analogs because they are similar but not exactly the same as nucleobases.
“You would not expect to see these nucleobase analogs if contamination from terrestrial life was the source, because they’re not used in biology, aside from one report of 2,6-diaminopurine occurring in a virus,” said Callahan.
“Finding nucleobase compounds not typically found in Earth’s biochemistry strongly supports an extraterrestrial origin,” Jim Cleaves of the Carnegie Institution for Science said in a press release.
Besides, ice samples from Antarctica and soil samples from Australia, both of which were taken from the location of the meteorite, were analyzed. However, nucleobase analogs were not found in either sample.
Moreover, the researchers were able to produce nucleobases in non-biological reactions involving hydrogen cyanide and ammonia, which are common in space. Therefore, these nucleobases do not necessarily need an Earth environment in order to form.
The findings will be published in the Proceedings of the National Academy of Science.
