A new type of bacteria has been discovered that uses poisonous arsenic to build its DNA.
All life on Earth was thought to have been composed of six elements: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur...until now. This newly-discovered microorganism, called GFAJ-1, was found in Mono Lake, California. The building blocks used to create its genetic material contain arsenic, which is poisonous to all but a few organisms on Earth!
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