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

Death and Jeff Bezos
Death and Jeff Bezos

Meet Altos Labs, Silicon Valley’s latest wild bet on living forever

Funders of a deep-pocketed new "rejuvenation" startup are said to include Jeff Bezos and Yuri Milner.

travelers walk through Ronald Reagan Washington National Airport
travelers walk through Ronald Reagan Washington National Airport

We won’t know how bad omicron is for another month

Gene sequencing gave an early alert about the latest covid variant. But we'll only know if omicron is a problem by watching it spread.

The miracle molecule that could treat brain injuries and boost your fading memory

Discovered more than a decade ago, a remarkable compound shows promise in treating everything from Alzheimer’s to brain injuries—and it just might improve your cognitive abilities.

surgery
surgery

A gene-edited pig’s heart has been transplanted into a human for the first time

The procedure is a one-off, and highly experimental, but the technique could help reduce transplant waiting lists in the future.

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.