By expanding the genetic alphabet, Sanofi researchers can pursue new medicines and improve existing therapeutics. 

DNA is composed of two pairs of chemical bases: adenine (A) and thymine (T), guanine (G) and cytosine (C). These letters make up the “genetic alphabet”, which provides all the instructions needed to create life. They provide instructions to use 20 amino acids to compose all the proteins in our bodies, which do everything from holding cell walls together to catalyzing biological reactions. 

These 20 amino acids also provide the raw material for creating protein therapeutics, for example interleukin-2 (IL-2) for treating cancers, and medicines to prevent infections.

Genetic alphabet illustration

Genetic alphabet illustration

What is the expanded genetic alphabet?

Scientists invented a new pair of DNA letters, nicknamed X and Y, that can be used in living systems. This invention led to the creation of an Expanded Genetic Alphabet by Synthorx, now part of Sanofi. Using six DNA letters instead of four, the Expanded Genetic Alphabet allows scientists to use novel amino acids to build new proteins.

Genetic alphabet illustration

Why does it matter?

These new proteins, called SYNTHORIN™ molecules, fill important gaps in protein therapeutics by vastly expanding the variety of building blocks available to bioengineers. This opens the door to creating new medicines, for example to re-program biological interactions that cause immune cells to attack healthy ones.

Used on its own or in combination with other Sanofi technologies, the Expanded Genetic Alphabet is enabling the company’s scientists and bioengineers to develop novel biologics for cancer and other diseases.

The Expanded Genetic Alphabet

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Voices from the Lab: Carolina Caffaro

Voices from the lab - Matthias Gunne

Voices from the Lab: Matthias Gunne

Pioneering Technology Platforms

MAT-GLB-2100163 | January 2021