Researchers get two genetic codes to work at the same time

The genetic code is what life everywhere uses to convert the information contained in DNA into specific protein sequences. With minor variations, the same genetic code is used by every living thing on Earth, suggesting it was already present in the last common ancestor of all of them. It's not an easy thing to change, because so many things in every cell depend on it.

Nevertheless, some preliminary steps have been taken. Researchers have managed to add some new amino acids to a bacterial cell and were able to make proteins that were one amino acid less than usual. But it's a slog; for some of this work, people have had to re-engineer every single gene in a bacterial genome.

Now, researchers have found a way to operate two separate genetic codes simultaneously, avoiding the need to do any work to compensate for altering the code that every protein in a cell relies on. They didn't test it in an actual cell, and it might cause some problems there. But it's a creative solution that should accelerate some synthetic biology work.

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Researchers try to cut the genetic code from 20 to 19 amino acids

The genetic code is central to life. With minor variations, everything uses the same sets of three DNA bases to encode the same 20 amino acids. We have discovered no major exceptions to this, leading researchers to conclude that this code probably dated back to the last common ancestor of all life on Earth. But there has been a lot of informed speculation about how that genetic code initially evolved.

Most hypotheses suggest that earlier forms of life had partial genetic codes and used fewer than 20 amino acids. To test these hypotheses, a team from Columbia and Harvard decided to see if they could get rid of one of the 20 currently in use. And, as a first attempt, they engineered a portion of the ribosome that worked without using an otherwise essential amino acid: isoleucine.

Changing the code

First off, why would you do this? Most work in the field has focused on altering the genetic code in ways that are useful, such as using more than 20 amino acids to enable interesting chemistry.

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