I had the same impression. This sounds really, really cool but it's still an organism that uses DNA, and we're still related to it. As a layperson, I don't see why this says a lot more about the potential for life elsewhere. If it's not a wholly new occurrence of life, then it's something that "did life" the same way we do until it happened to need this really cool adaptation.
I understand that my lack of biology training probably contributes to my not getting it, but that's where most people are coming from. A lot of time has been spent explaining the significance of Einstein's work and most people still don't "get it", we may need the same here.
So, instead of snarking...explain again/better/differently than others have.
We don't know of any form of life that isn't related to us at all. We have no strong evidence that such life has ever existed (although we have reasons to believe that it could have, before DNA-based life ate it all). For such life to exist on Earth today, it would have to compete with our relatives, and that's hard to do now, as it has been for billions of years.
So if nothing short of finding a completely unrelated living organism is going to excite you, the odds are strongly in favor of your being bored with biochemistry for as long as you live. Better change the channel.
All I know about biochem is what I learned by listening to Lander and Weinberg on MIT OpenCourseWare, but even I know that (a) every lifeform on earth has phosphorous-based chemicals at the center of its metabolic mechanism; (b) every lifeform on earth uses phosphate-based chemistry -- DNA or RNA, specifically -- as its genetic mechanism. These are the things you learn in the freshman class. Evidence that there might be an organism alive right now that violates one or both of these rules, even partially, is very exciting.
With our luck, they made some kind of mistake, and we can all go back to the status quo once they find the error, get totally drunk, and then issue an apology. But, if not, whole careers in biochemistry will be spent studying this.
> This sounds really, really cool but it's still an organism that uses DNA
Are we 100% certain of that? I'm not a biologist, however it seems to me that DNA is in part defined by the usage of Phosphorus. Maybe we need to redefine DNA? Or does this organism not use DNA at all?
Yeah, I don't know either. Sounds like DNA is the strand/mechanism and using phosphates is all we know of so far. IANAS
But if it's not-technically-DNA-anymore because it can use an arsenate instead of a phosphate, it's still part of our tree of life. That's the part that seems to have dampened enthusiasm somewhat.
I think it's more that this isn't very game-changing. Einstein revolutionized physics with relativity; Darwin revolutionized biology. What does this discovery revolutionize? Biochemistry perhaps, but it seems a bit too specific to have far-reaching impacts.
Talk about a life-changing discovery!