casper
12-04-2010, 04:49 PM
Find could change search for alien life
WASHINGTON, -- A U.S. researcher says she has found an Earthly bacteria that breaks the biochemical "rules" all life on the planet was thought to follow.
All known life on Earth is based on a single genetic model that requires six essential elements: carbon, oxygen, hydrogen, nitrogen, sulfur and phosphorus.
But biochemist Felisa Wolfe-Simon has discovered a bacterium that has five of those essential elements but has, in effect, replaced phosphorus with its look-alike but toxic cousin arsenic, The Washington Post reported Thursday.
At a NASA news conference Thursday, the researcher said the discovery opens the door to the possibility of the existence of a theorized "shadow biosphere" on Earth -- life evolved from a different common ancestor than all that we've known so far -- and could impact the search for life on alien worlds.
"Our findings are a reminder that life-as-we-know-it could be much more flexible than we generally assume or can imagine," Wolfe-Simon, a member of the National Astrobiology Institute team at Arizona State University, says.
"If something here on Earth can do something so unexpected -- that breaks the unity of biochemistry -- what else can life do that we haven't seen yet?" she said.
Her research, funded through NASA and conducted with samples from California's Mono Lake, found some of the bacteria not only used arsenic to live, but had arsenic embedded in their DNA, RNA and other basic chemistry.
"This is different from anything we've seen before," said Mary Voytek of NASA's program in astrobiology, involved specifically in the search for life beyond Earth and for how life began here.
The discovery goes to one of the central challenges of astrobiology: knowing what to look for in the search for extraterrestrial life.
"One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should 'follow the elements,' " ASU biogeochemist Ariel Anbar says.
"Felisa's study teaches us that we ought to think harder about which elements to follow."
WASHINGTON, -- A U.S. researcher says she has found an Earthly bacteria that breaks the biochemical "rules" all life on the planet was thought to follow.
All known life on Earth is based on a single genetic model that requires six essential elements: carbon, oxygen, hydrogen, nitrogen, sulfur and phosphorus.
But biochemist Felisa Wolfe-Simon has discovered a bacterium that has five of those essential elements but has, in effect, replaced phosphorus with its look-alike but toxic cousin arsenic, The Washington Post reported Thursday.
At a NASA news conference Thursday, the researcher said the discovery opens the door to the possibility of the existence of a theorized "shadow biosphere" on Earth -- life evolved from a different common ancestor than all that we've known so far -- and could impact the search for life on alien worlds.
"Our findings are a reminder that life-as-we-know-it could be much more flexible than we generally assume or can imagine," Wolfe-Simon, a member of the National Astrobiology Institute team at Arizona State University, says.
"If something here on Earth can do something so unexpected -- that breaks the unity of biochemistry -- what else can life do that we haven't seen yet?" she said.
Her research, funded through NASA and conducted with samples from California's Mono Lake, found some of the bacteria not only used arsenic to live, but had arsenic embedded in their DNA, RNA and other basic chemistry.
"This is different from anything we've seen before," said Mary Voytek of NASA's program in astrobiology, involved specifically in the search for life beyond Earth and for how life began here.
The discovery goes to one of the central challenges of astrobiology: knowing what to look for in the search for extraterrestrial life.
"One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should 'follow the elements,' " ASU biogeochemist Ariel Anbar says.
"Felisa's study teaches us that we ought to think harder about which elements to follow."