NASA scientists have discovered the first known microorganism (GFAJ-1) on Earth capable of reproducing and thriving on a highly toxic chemical known as arsenic.
The microorganism - which substitutes arsenic for phosphorus in its cell components - was found in California’s rugged hypersaline Mono Lake.
GFAJ-1 was then transferred to a laboratory, where researchers successfully grew microbes on a diet that was very lean on phosphorus, but included generous helpings of arsenic.
Surprisingly, when lab technicians removed the phosphorus and replaced it with arsenic the microbes continued to grow.
Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new GFAJ-1 cells.
"The definition of life has just expanded," said Ed Weiler, NASA's associate administrator for agency’s Science Mission Directorate.
"As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it."
According to NASA, the discovery of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.
"We know that some microbes can breathe arsenic, but what we've found is a microbe doing something new - building parts of itself out of arsenic," explained Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow and the research team's lead scientist.
"If something here on Earth can do something so unexpected, what else can life do that we haven't seen yet?"