The most recent and biggest news to the academic community has came from NASA these days. They just announced the evidences of new life form and claimed the GFAJ-1 strain can live under the environment without Phosphorus but using Arsenic instead. To me they still haven't shown the direct evidence that Arsenic directly replaced the P in phosphodiester bond of DNA backbone, ATP and other molecules.
Not only for lacking of direct evidence (eventhough the isotope labelling showed the radioactivity came with nucleic acid fraction together, it could still be interpreted as a contamination), it is also still arguable about the stability of As-O bond. From chemical viewpoint, the As-O bond is very unstable and much weaker than P-O bond. Really don't know how does this tiny creature work with Arsenic.
