December 2, 2010 on Al-Jazeera English
See also: NASA Press Conference (Thanks to TheRationalizer)
NASA has discovered a new life form, a bacteria called GFAJ-1 that is unlike anything currently living in planet Earth. It's capable of using arsenic to build its DNA, RNA, proteins, and cell membranes. This changes everything. Updated.
NASA is saying that this is "life as we do not know it". The reason is that all life on Earth is made of six components: Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same.
That was true until today. In a surprising revelation, NASA scientist Felisa Wolfe-Simon and her team have found a bacteria whose DNA is completely alien to what we know today, working differently than the rest of the organisms in the planet. Instead of using phosphorus, the newly discovered microorganism—called GFAJ-1 and found in Mono Lake, California—uses the poisonous arsenic for its building blocks. Arsenic is an element poisonous to every other living creature in the planet except for a few specialized microscopic creatures.