Scientists have found that all five of the substances that make up DNA and RNA in samples from Ryugu, the asteroid Japan’s Aerospace Exploration Agency visited in 2020.
As outlined in a paper titled “A complete set of canonical nucleobases in the carbonaceous asteroid (162173) Ryugu” that appeared in the journal Nature Astronomy this week, analysis of samples from Ryugu turned up “all five canonical nucleobases – purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil).”
That matters because “The purines adenine and guanine and the pyrimidines cytosine, uracil and thymine constitute the base sequences of DNA and RNA that encode and transmit genetic information.”
And they were all floating around in an orbit between Earth and Mars.
“This implies that the molecular prerequisites for life are not unique to Earth and may emerge as natural products of chemical evolution throughout the Solar System,” the paper states.
There’s more: “Nucleobases could have been delivered to the early Earth, potentially contributing to the molecular inventory necessary for life,” the paper argues. “Furthermore, elucidating the formation mechanisms of extraterrestrial nucleobases helps to constrain the universal physicochemical conditions under which they can form abiotically, thus linking astrochemical processes in interstellar and planetary environments to the chemical evolution that preceded the origin of life.”
The authors drew those conclusions after considering samples from Ryugu, plus the Bennu asteroid visited by NASA in 2023, and the Orgueil meteorite, a space rock that landed in France in 1864.
Samples taken from Bennu also indicate the presence of the five canonical nucleobases.
Scientists believe Orgueil also contained the nucleobases uracil, adenine, and guanine.
Japan’s Agency for Marine-Earth Science and Technology, which curated the samples from Ryugu, interpreted the paper as indicating “the fundamental components of genetic material were likely produced universally during the formation of the Solar System, providing important direct evidence for early chemical evolution.”
“The relative abundance of purine and pyrimidine nucleobases in Ryugu reflects their formation pathways,” the agency asserted. “A clear correlation between the purine-to-pyrimidine ratio and ammonia abundance led us to propose a new molecular indicator of non-biological nucleobase evolution.”
That suggests that our Solar System cooked up the stuff of life as it formed.
And billions of years later, an entity whose existence may just be due to those strange cosmic processes is bringing you the news in The Register. ®
Source: The register