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Life As We Don't Know It

December 3, 2010

Rheanna Sand

Blog by Rheanna Sand

 

Before I explain what I love about "arsenic life," I must rant. What the heck was with that press conference? NASA took a game-changing biological discovery and turned it into NOT AN ALIEN. Reading the website beforehand, you would think Dr. Ellie, or some old dude stealing credit for her work, would announce we had made contact! Instead we get Made-in-America bacteria and bad props. This could have been really cool if it wasn’t' so blatantly designed to tug at the science fiction heartstrings of nerds like me.

And, no, this spite has nothing to do with Irene from Discovery getting the last question during the Q&A. But I was SO SURE when they said "let's go to the West Coast," they meant Edmonton, Alberta, Canada!

With that said, this research really does change they way I think about life. I became a biologist to learn about how organisms function. From the whole being, to the organ systems, to the cells, to the organelles within those cells and the biomolecules that make them up, finally to the atoms that constitute those molecules. One of the most fascinating facts revealed by this level of detail is that of the whole periodic table, life forms are made up of only six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur. We use trace metals in our enzymes, and iron in our hemoglobin, but all life is made up of those six elements. It always felt so limiting: we need these six ingredients, on a planet with this much air, this far away from a star just that bright.

 


 

But the Mono Lake, California bacteria can live on arsenic. GFAJ-1 prefer phosphorus, but when given a diet enriched with arsenic, they incorporate it into the DNA backbone as an "arsenate," replacing phosphate. The researchers used, among other methods, micro X-ray absorption spectroscopy (a really powerful chemical detector) and found it not only in DNA, but in ATP, acetyl-coA, and NADH, biomolecules involved in metabolism.

If this can happen on Earth, this leads me to think that the machinery of life might not be limited to this sliver of our solar system where the conditions are just right. Who is to say what is "just right"? There could be a different sliver in a nearby solar system where the atmospheric pressure and alkalinity is perfect for something I can't even imagine.

So, despite the bad props, I can at least thank the NASA researchers for that.

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