Recent discoveries have confirmed that all five nucleobases essential for DNA and RNA—adenine, guanine, cytosine, thymine, and uracil—have been detected in meteorites, specifically carbon-rich ones like Murchison, Murray, and Tagish Lake.

These nucleobases, which form the genetic code of life, were identified using advanced analytical techniques, including gentle extraction with cool water and highly sensitive mass spectrometry, allowing detection down to parts per trillion.

This breakthrough, reported in Nature Communications in 2022, builds on earlier findings of adenine, guanine, and uracil, with cytosine and thymine previously elusive due to their fragile structures. The presence of these compounds in meteorites supports the hypothesis that life’s building blocks could have originated in space, delivered to Earth via meteorite impacts during its formative years.

However, some scientists, like Michael Callahan, caution that terrestrial contamination might contribute to these findings, as soil samples near meteorite sites showed higher concentrations of some nucleobases. The detection of unique isomers in meteorites but not in surrounding soil strengthens the case for an extraterrestrial origin. Ongoing analyses of asteroid samples, such as those from Ryugu and Bennu, aim to further clarify these compounds’ cosmic origins.