An international team with NASA researchers has found two informational units that make up DNA and RNA in meteorite samples. Researchers can now claim that all five nucleobases – adenine, thymine, cytosine, guanine, and uracil – are present in space.
This time, the researchers found cytosine and thymine in meteorite samples. The other three nucleobases, including adenine, guanine, and uracil, have been found in space objects before.
“We now have evidence that the complete set of nucleobases used in life today could have been available on Earth when life emerged,” said Danny Glavin, a co-author of the paper.
Scientists suggest that cytosine and thymine were hard to detect in previous analyses because of their delicate structure. In earlier experiments, scientists placed grains of meteorite in a hot bath of formic acid. After that, the experts analyzed the molecular composition of the resulting extraterrestrial broth, but because formic acid is very reactive, cytosine and thymine molecules could degrade in it.
This time, the scientists used cool water instead of hot acid to extract the compounds, and they were able to extract the delicate compounds.
It is still unknown whether these basic components for life came from outer space or were instead formed in the warm soup of earthly chemistry. But the discovery adds to the evidence that life may have originally come from space, researchers say.