Skip to Content
Biotechnology

Researchers have swapped the genome of gut germ E. coli for an artificial one

By creating a new genome, scientists could create organisms tailored to produce desirable compounds.
Micrograph of E. coli
Micrograph of E. coli
Micrograph of E. coliNIAID

Researchers say they have replaced all the genes of E. coli  bacteria with a complete copy of the genome synthesized in the lab. It’s a step toward creating germs that are genetically tailored to make a specific materials such as Kevlar or other polymers.

Scientists at the University of Cambridge report in Nature how, in a stepwise fashion, they gradually replaced the organism’s entire genome—it has 4 million DNA letters—with artificially made genes.

“It took two years, but we’d like to get this to the point where we can manufacture new synthetic genomes in less than a month,” says Jason Chin, a biologist with the UK Medical Research Council, who led the team. “That would massively accelerate the field, the number of things we can make and test.”  

The first synthetic bacterial genomes were created in 2008 and 2010 at the J. Craig Venter Institute. But the E. coli genome, which is four times their size, sets a new record.

A separate consortium is trying to create baker’s yeast with artificial genes, but that project is not yet complete.

In replacing the bacterium’s genome, Chin’s team also simplified it by replacing some of the three-letter DNA instruction sets, or codons, that cells use to determine which of 20 amino acids they’ll add to a protein.

In the end, Chin’s E. coli has only 61 codons instead of the usual 64.

That means the new species of germs, called Syn61, don’t only have man-made genes, but also show that an organism can live with what the UK team calls a “compressed” genetic code.

“One is a technical achievement; the other tells you something fundamental about biology and how malleable the genetic code really is,” says Chin.

Simplifying the E. coli genome means the unused parts of the code are now free to do other things. For instance, they could be repurposed so that bacteria make proteins involving any of a couple of hundred amino acids that life doesn’t normally make use of. That could lead to the manufacture of unusual polymers in bacteria, like the material that goes into bulletproof vests.

There is also a scientific question, says Chin. Ever since the 1960s, when scientists first cracked the code, it’s been unclear exactly why it works the way it does—out of so many possibilities, why this one?

In 1968, Francis Crick, the co-discoverer of DNA’s chemical structure, proposed the “frozen accident” theory. Once basic life forms evolved, he suggested, the triplet codes got locked into place because any deviation from the universal program would be a big disadvantage. “By removing codons, we’re breaking that common language,” says Chin. “We’re unfreezing the code.” 

Deep Dive

Biotechnology

He Jiankui
He Jiankui

The creator of the CRISPR babies has been released from a Chinese prison

He Jiankui created the first gene-edited children. The price was his career. And his freedom.

Aging Clocks concept
Aging Clocks concept

Aging clocks aim to predict how long you’ll live

These clocks promise to measure biological age and help identify anti-aging drugs, but there are lingering questions over their accuracy.

transplant surgery
transplant surgery

The gene-edited pig heart given to a dying patient was infected with a pig virus

The first transplant of a genetically-modified pig heart into a human may have ended prematurely because of a well-known—and avoidable—risk.

locked-in patient communicates via computer
locked-in patient communicates via computer

A locked-in man has been able to communicate in sentences by thought alone

In a world first, the man was able to ask for soup, beer, and even talk about his son for the first time since becoming completely paralyzed.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.