Some people are concerned about the risks of GMOs spreading beyond their intended purpose as they have the potential to damage the environment.

Two groups of researchers, however, have come up with genetically engineered bacteria that depend on lab-formulated amino acids in order to survive. The bacteria's dependence on lab-made food means that they would die off once they escape from a carefully controlled environment, and this could make GMOs safer in an open environment.

In a pair of studies published in the journal Nature on Jan. 21, two groups of researchers developed strains of E.coli bacteria that need synthetic amino acids for survival. Such genetic firewall means that GMOs that somehow escape from a laboratory, a manufacturing facility or an agricultural field would not survive.

To create the genetically engineered bacteria dubbed genomically recoded organisms (GROs), the researchers used new genetic engineering techniques in order to rewrite the DNA of E.coli, adding sequences into some genes that are essential for the survival of the bacteria so they cannot evolve and get rid of these changes.

"The resulting GMOs cannot metabolically bypass their biocontainment mechanisms using known environmental compounds, and they exhibit unprecedented resistance to evolutionary escape through mutagenesis and horizontal gene transfer," wrote George Church from the Department of Genetics at the Harvard Medical School in Boston and colleagues. "This work provides a foundation for safer GMOs that are isolated from natural ecosystems by a reliance on synthetic metabolites."

The other research team led by Farren Isaacs from the Department of Molecular, Cellular and Developmental Biology at Yale University was also able to modify the same E.coli strain to depend on synthetic amino acid albeit using a different method.

"We describe the construction of a series of genomically recoded organisms (GROs) whose growth is restricted by the expression of multiple essential genes that depend on exogenously supplied synthetic amino acids (sAAs)," Isaacs and colleagues wrote.

Although genetically modified bacteria are already used for producing drugs, chemicals, milk and dairy products, there are concerns that these could have unwanted effects on the environment and thus their uses are being limited.

The two newly published studies are the first to use dependence on synthetic nutrient as a biocontainment strategy for GMOs. The methods employed may pave the way for more widespread uses and applications of GMOs such as cleaning up oil spills and improving food production.

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