“The DNA of nearly all life on Earth is made up of 64 codons, each one a sequence of three nucleotide bases, the building blocks of DNA. These codons contain instructions for building amino acids, which, in turn, combine to form proteins. But having so many codons is redundant—cells use only 20 amino acids, so some of them end up being coded for multiple times.

That’s why scientists have been working to ‘free up’ codons from microbes, or remove them and shorten the genetic code. They hope to one day repurpose some of these sequences so that, instead of encoding amino acids that are already accounted for, they might code for other amino acids that don’t occur naturally. This could make the microbes produce new molecules that might lead to useful drugs or materials. It might even make the microbes virus-resistant.

Now, scientists have redesigned the genetic code of the bacterium Escherichia coli to contain just 57 of the 64 codons. The findings were published in late July in Science.”

From Smithsonian Magazine.