New microorganism is like "cracking open the door & finding what we think are fixed constants of life are not"

Scientists have discovered bacterium able to use arsenic to build DNA and other molecules, changing the fundamental knowledge about what comprises all known life on Earth. Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.