Sadly, NASA’s press announcement failed to be the alien UFO disclosure we were all hoping and wishing for. Even the more reality-based speculation about discovering evidence of microbial life on Mars or Titan turned out to be a bust. But one lonely blogger did some foot work and guessed the results of the paper nearly a full day in advance of the embargoed publication date. While the majority of the people on earth probably do not understand or even care about the result, it is probably the most significant finding since the components of DNA were originally parsed.
There was a Star Trek Episode where the crew finds a silicon based life form buried in a deep mine on an alien planet. (Geek Alert Season 1, Episode 25 The Devil in the Dark, the silicon based life form is the Horta)
(Photo from http://en.wikipedia.org/wiki/The_Devil_in_the_Dark)
The idea was that the carbon in our DNA can be replaced by silicon, an atom that is right above carbon on the Periodic Table, and so is capable of performing many of the same chemical reactions. While nobody has found a silicon DNA or protein component, this new paper announces a similar substitution of a life-sustaining atom in a real-live Earthling bacteria.
The Science paper, announced today in a NASA Press Release briefing, states that the phosphorus found in DNA is replaced with arsenic in a strain of bacteria found in Mono Lake, CA. Here is the Science abstract. http://www.sciencemag.org/content/early/2010/12/01/science.1197258 But there is a significantly more detailed summary on the Arizona State University website that was pointed to me by my ASU mentor Ariel Anbar, a coauthor. http://asunews.asu.edu/20101202_arsenic
The significance of the announcement is that if substitutions for life-necessary elements can be found, then it is feasible that life processes can occur by entirely different chemical paths than what we generally find here on earth. Instead of looking for a fairly strict ratio of elements that we find in DNA, the search for life must be expanded to include any number of possible permutations that could lead to life. And the best part is that, at this time, we can not necessarily predict what elements will lead to life.
All in all, very cool. It tickles me a little bit to have worked in one of the labs that produced these results, even for a few months, without success on my project. Ariel’s a good guy and I anticipate many more significant results coming from the Keck lab at ASU.
Also, as a note, one of the big side issues that came out of this story is how the Science and Nature embargo system in tandem with the highly suggestive NASA press release caused trouble. I have a strong feeling that the scientists who wrote the paper felt like they were hogtied during the embargo while crazy speculation bounced around the internet. Additionally, the press release was extremely suggestive and lead to a lot of hype in a fairly technical topic that may have harmed the public confidence in science. I hope there are some lessons learned from this announcement that will be considered in future press releases.
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