Argh. Once again, the biggest science story of the week is a bit of a mess. NASA didn't help by teasing everyone with its advance press release/PR stunt about an "astrobiology discovery." The news was nothing of the sort. Rather, scientists have found some very weird life—on Earth.
The real story is fascinating, if you're into biology. Bacteria that appear to be able to substitute arsenic in place of phosphorus in the very structure of their DNA (and other bioactive molecules)—that's extremely cool. It shows how innovative natural selection can be, because as PZ Myers points out, the reason arsenic is usually lethal to living things is precisely because it's chemically so similar to phosphorus (and nitrogen). Usually, however, it screws up biochemical processes that it gets mixed into. These newly-discovered bacteria from salty, alkaline Mono Lake in California have managed to co-opt arsenic instead of being killed by it.
UPDATE December 7, 2010: Actually, maybe they haven't done so after all, and this whole ruckus has been a complete waste of time. Here, read some more.
But the publicity and news coverage remind me of the hoopla over Ida and Ardi, the fossil primate discoveries touted last year. Again, cool science, but woefully misrepresented to the public in its importance and meaning. The connection between the GFAJ-1 bacteria from Mono Lake and potential extraterrestrial life (which, I remind you, no one has yet found any evidence of) is so tenuous it's almost nonexistent: these critters tell us that it's possible for life to use a slightly different chemistry.
But we're not talking about life based on silicon instead of carbon. This is a less fundamental difference. The bacteria in question still use DNA. In the wild, in Mono Lake, they still use phosphorus, and indeed they're healthiest when they do. But in the lab, they can be coaxed into using arsenic instead, rather than simply dying in messy heaps like the rest of us earth beings would. Those are the basics.
I guess it makes sense, in a way, for NASA to hype up the story. A press release titled "Biologists discover life can use slightly different chemistry" wouldn't bring out CNN, but hype also has its risks:
The problem is that hype can lull us into a cry-wolf syndrome. If people hear about an amazing set of "missing links!!!" (but oh, they aren't) and "signs of extraterrestrial life!!!" (but oh, they're terrestrial), are we going to take it seriously when scientists say, for instance, "Hey, global climate change looks like it's going to be a big problem"?
Many policy makers in the U.S. and elsewhere are already too ignorant about important scientific issues today, even about such essential ideas as how petroleum forms, the reality of evolution, or the usefulness of paying for basic research. Bait-and-switch tactics with scientific announcements surely don't help.
An excellent post, Derek, and very good points about scientists being taken seriously on other topics.
You know, I'm a sci-fi fan so have often read or watched stories about alternate life forms, but it had never occurred to me they might not use DNA. Thanks for opening my eyes on that score. :-)
As for people being ignorant on important scientific issues - that touches on something I've been thinking about a lot lately. I'm no scientist. I did some physics at high school, back in the 60's. I hated biology with a passion and was utterly bamboozled by chemistry.
As an adult though I'm extremely interested in all these things, but it's 40 years on and the world has changed.
For one thing, I've forgotten anything I might ever have thought I'd known. For another, science has discovered new things and discredited old things.
I feel scientifically (and mathematically) illiterate. And *I'm interested and curious*! I listen to podcasts, read news items, watch science-y videos and TV shows (if they ever exist).
I wish there were stuff for adults that *teach* the basics of science - in an interesting way, and from the beginning.
I haven't finished my own private ponderings on this, but there I am blurting it out for the first time, for what it's worth.
I think NASA's arsenic-life announcement would have deserved some of the hype - this is a proof-of-concept result that different chemistries can support life - if the results hadn't been signed, sealed and delivered before the press conference even took place.
I honestly don't know how anyone can make an announcement like this anymore, and keep the result secret until the big moment. People are as curious as ever and with google and twitter, every one of us can "break the story" in just a few clicks. That transparency is a good thing, I think. But I don't envy the PR people who try to orchestrate the release of a discovery like this.