NASA Discovers a Truly Unique Life Form December 3, 2010Posted by Metabiological in Beyond Earth.
Tags: alien, astrobiology, NASA
Well it’s not quite first contact but it’s pretty much the next best thing. NASA announced yesterday that it had discovered a new species of bacteria living in a fairly unlikely place: Mono Lake, California. Not only is the lake highly alkaline and very salty, neither of which is good for most life, it contains high amounts of the highly dangerous compound arsenic. Arsenic is poisonous to most creatures on Earth but despite that the lake does actually have a simple ecosystem. Finding a bacteria that thrives in such extreme conditions is cool but not particularly noteworthy.
What is note worthy is what else the found. The bacteria not only survives but actually uses the arsenic in the construction of its DNA. Why is that interesting? Because it’s supposed to be impossible.
Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.
Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.
Get it now. This is not just another extremophile. This species actually possesses a unique biochemistry, different from all other life on this planet. It expands the borders of what must be considered life. It also has important implications for the search for extraterrestrials.
Up till now scientists have been focusing there attention on looking for life like us. Not us as in humans or even vertebrates but life based off a similar blueprint: liquid water, oxygen breathing, carbon based. All of these are good assumptions since as far as we know that’s what life is like. Sorry, as far as we “knew.” What was once just a popular trope for science fiction writers is now a scientific theory with evidence to back it up. It drastically expands the places where the search for life can take place. Again, not quite first contact but I’ll take it.
P.S. Yes I’m aware that at this point this is old news. I’m a grad student, cut me some slack.