When NASA began thinking about missions to look for life beyond Earth, it realized it had a problem: how to recognize life if it were found.
Scientists came up with a definition for life — a self-sustaining chemical system capable of Darwinian evolution — but remained understandably fuzzy on the details.
It is still not known how life on Earth took hold, what happened to a bunch of chemicals that made them capable of supporting a metabolism, replicating and evolution. But a new field of science, called synthetic biology, is aiming to find out.
One of the most promising developments lies in a beaker of water inside a Florida laboratory. It’s an experiment called AEGIS — an acronym for Artificially Expanded Genetic Information System. Its creator, Steve Benner, says it is the first synthetic genetic system capable of Darwinian evolution.
AEGIS is not self-sustaining, at least not yet, and with 12 DNA building blocks — as opposed to the usual four — there’s little chance it will be confused with natural life. Still, Benner is encouraged by the results.
“It’s evolving. It’s doing what we designed it to do,” said Benner, a biochemist with the Gainesville, Fla.-based Foundation for Applied Molecular Evolution.
