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There has been considerable progress in trying to create artificial life based on completely different building blocks than all other life on Earth.

Researchers have for example managed to insert foreign building blocks into the DNA of bacteria. But now, the private research institute Scripps in California has taken another important step, as they have made bacteria that use artificial DNA to produce new kinds of proteins.

All life on Earth is based on the same genetic system. DNA acts as a kind of drawing board with instructions on how to construct the proteins that construct and are involved in all kinds of activities in our cells.

The technical language of the drawing board consists of long chains of a certain kind of molecules that exist in four forms and whose names are shortened by A, T, G and C. Four letters in total.

The study published in the journal Nature by researchers working at the Scripps research institute describe how they introduced two new “letters” in the DNA. They call them X and Y.

“I would not call this a new lifeform—but it’s the closest thing anyone has ever made,”

“This is the first time ever a cell has translated a protein using something other than G, C, A or T.”

– TSRI Professor Floyd Romesberg, Ph.D., who led the study.

The letters were inserted at places where the cell reads the drawing to produce proteins. And even with the new foreign elements, protein production worked well.

Fluorescent cells express a protein encoded by artificial DNA bases. Credit: Bill Kiosses, The Scripps Research Institute

Since the foreign DNA characters provide instructions on building new types of building blocks into proteins, the proteins cannot be manufactured in nature.

The goal is to be able to tailor new drugs. But so far, researchers have only tested with a green luminous protein to illustrate that the idea works.


Yorke Zhang et al. A semi-synthetic organism that stores and retrieves increased genetic information. Nature November 29, 2017. DOI: 10.1038 / nature24659