A paper announcing the discovery of four DNA bases in an asteroid on Monday made headlines. But most of the headlines missed the key word needed to put the discovery in context: “again.” The paper itself cited similar findings from 2011, and various confirmations and more rigorous investigations have followed in the years since. The new work drew less attention for showing that we found these bases in Ryugu than for solving the previous mystery: previous studies failed to detect them there, even though they were in many other asteroid samples.
Beyond the headlines, the new work provides some interesting details, as it may answer an important question: how those grounds got there in the first place. A better understanding of this could be critical to gaining a better understanding of how the raw materials for life ended up on Earth in the first place.
Bases are searched
Let’s start with a description of what the researchers found. DNA and RNA, the two nucleic acids used by life, have similar structures. It includes a backbone, a chain that alternates between sugars and phosphates, all of which are chemically linked together. Although the specific sugar differs between DNA and RNA, the chain itself varies only in length; otherwise, the backbone of each DNA or RNA molecule is identical.
