New Advance Confines GMOs To the Lab Instead of Living In the Wild

BarbaraHudson (3785311) writes In Jurassic Park, scientists tweak dinosaur DNA so that the dinosaurs were lysine-deficient in order to keep them from spreading in the wild. Scientists have taken this one step further as a way to keep genetically modified E. coli from surviving outside the lab. In modifying the bacteria's DNA to thwart escape, two teams altered the genetic code to require amino acids not found in nature. One team modified the genes that coded for proteins crucial to cell functions so that that produced proteins required the presence of the synthetic amino acid in the protein itself. The other team focused on 22 genes deemed essential to a bacterial cell's functions and tied the genes' expression to the presence of synthetic amino acids. For the bacteria to survive, these synthetic amino acids had to be present in the medium on which the bacteria fed. In both cases, the number of escapees was so small as to be undetectable."

Comments

Quick history lesson

[Okian Warrior]

Way back in the 1970s, a scientist named Roy Curtiss engineered Chi-1776: a strain of E. Coli for precisely these purposes. It was unable to synthesize d-amino pimelic acid, it couldn't exchange plasmids(*) with other bacteria, it was killed by detergents and UV radiation, and so on.

It was subsequently discovered that the survival of Chi-1776 was greatly enhanced when a plasmid commonly used for research was added.

Chi-1776 was also found difficult to work with. The very safeguards that made it safe for experimental use also made it difficult to grow. In fermentors it was outcompeted by just about everything else in the environment, so absolutely sterile environments were required, and this turns out to be very difficult in practice.

In response, researchers turned to a strain labelled K-12 which had a higher survival rate than Chi-1776, but couldn't infect the digestive tract and also couldn't survive in the wild.

...until it was found to infect mouse digestive tracts after the mice had been given certain antibiotics.

Also, despite strict procedures in place for chemical or physical disinfection, K-12 was subsequently found in the sewer systems supporting the University of Texas.

Those who cannot remember history are doomed to repeat it, or so they say. Does that statement apply to the current situation?

(*) A plasmid is a "loop" of DNA that is sometimes exchanged between bacteria. It's a method of propagating useful survival traits without going through the full reproductive cycle.