Since the beginning of time, the genetic alphabet in all living things has consisted of 4 letters. Now, scientists have discovered a way to expand the genetic code to store and use orders of magnitude more information than ever before.

Deoxyribonucleic acid (DNA) is the cellular instructions for proteins: little machines in your cells that perform important functions. DNA normally contains 4 nucleotides (A, T, G, and C) as the “letters” in the genetic alphabet. Arranging them in 3-letter “words” creates the code for amino acids, the building blocks to make proteins. In 2014, scientists reprogrammed bacteria to incorporate 2 more nucleotides (X and Y) using the cell’s own DNA-making machinery. However, those nucleotides couldn’t be used to code for new amino acids, making them functionally inactive.

Now, the same scientists have made their new nucleotides functional. The team has successfully used their new genetic code to incorporate novel amino acids into a special protein, called green fluorescent protein (GFP) in E. coli bacteria. This is the first time scientists have made proteins with the expanded genetic code.

The traditional 4-letter code provides 64 possible 3-letter words (43), yet there are only 20 amino acids, so most amino acids have multiple words as codes. With the expanded 6-letter code, there are 216 possible 3-letter words (63), corresponding to up to potentially 172 amino acids – 8.5 times more!

Of course, this breakthrough synthetic biology could be used to make much more than glow in the dark E. coli. Such an incredible feat can be utilized to make new drugs, materials, and even life forms!

Managing Correspondent: Chelsea Weidman

Press Articles: Scientists just added two functional letters to the genetic code. Science.

Six-Letter DNA Alphabet Produces Protein in Cells. The Scientist.

‘Alien’ DNA makes proteins in living cells for the first time. Nature News.

Original Journal Article: A semi-synthetic organism that stores and retrieves increased genetic information. Nature.

Image Credit: intechopen.com