Scientists have engineered a bacteria with a genetic 'kill switch'

Genetic engineers have designed strains of E. coli bacteria that can survive only in the presence of a synthetic amino acid that does not exist in the natural environment — meaning that if these bacteria escape the lab, they should, in theory, eventually die.
“Amino acids are the essential building blocks that all proteins are made of in all forms of life,” explains Dan Mandell, a research fellow in genetics at Harvard Medical school in Boston and co-author on a study about the work in the journal Nature.
“Because our amino acid is synthetic, meaning it must be manufactured in the lab, our organisms can't find it in the wild. So we can control where the organism will grow by adding or removing the synthetic amino acid from the organism’s food source," he says.
Modified bacteria and other organisms are already used to produce things like commodity chemicals and medicines, but this is the first one with a built-in ‘kill switch’ designed to keep it under control outside the laboratory.
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