Quote:It was my understanding that the scientists artificially substituted Arsenic for Phosphorus in these microorganisms and that they continued to survive afterward, but I may be mistaken.
From what I have read they took a bacteria that is known to "tolerate" arsenic rich environments and put them into extremely phosphorus poor and arsenic rich environment. The only phosphorus was what was residual to the initial samples while massive doses of arsenic were added. A control group was set up using the opposite technique, a phosphorus rich and arsenic starved environment.
In each case the bacteria thrived and reproduced over multiple generations. The control group continued to use the phosphorus as it's DNA building block material while the experimental group managed to substitute the phosphorus with arsenic.
As yet the "HOW" question remains unanswered.