A Startup Is Pushing the Boundaries of Biology with Synthetic DNA

Biotechnology company Synthorx has taken the next step towards creating truly synthetic life.

Dr. Floyd Romesberg, one of the company's co-founders, made news last year when he and a team of scientists successfully incorporated two synthetic nucleotide bases into the DNA sequence of a strain of E.coli bacteria. In a announcement yesterday, the company claimed to have taken its research a step further by incorporating and replicating brand new amino acids made with these synthetic bases into proteins.

It sounds like the stuff of sci-fi, but Synthorx is creating organic compounds that don't exist anywhere in nature. This research would primarily form the basis for the development of new pharmaceutical drugs.

DNA is made up of four base pairs of compounds called nucleotides that are immediately recognizable: adenine (A) and thymine (T), and guanine (G) and cytosine (C). Combinations of just these four bases forms the genetic material of every living thing in nature, and serve a lot of different purposes, including coding for the production of amino acids.

The scientists at Synthorx have introduced two new bases, d5SICSTP (X) and dNaMTP(Y), and have inserted them into E. coli bacteria's DNA, where they've been successfully paired with the four natural bases. (E. coli strains reproduce very quickly, and so make for the perfect test subject for experiments like this.) Researchers add the synthetic bases to natural E.coli genetic material and stimulate a reaction of the genetic material into a new protein. The next step is to get bacteria to adapt these synthetic nucleotides naturally and form proteins completely on their own.

Adding just two new bases to the natural four opens up the possibility of creating brand new amino acids beyond the 20 standard amino acids that form the basis of the vast majority of proteins in living organisms. As proteins are workhorses in living organisms that do everything from building muscle tissue to forming antibodies that fight disease, the hope is that developing entirely novel proteins could be used for new medical treatments.

Synthorx claims they've used these new amino acids to code brand new protein structures. Synthorx rightfully points out all the new drugs and treatments we could synthesize with new amino acid combinations, but if you want to get really sci-fi, they could theoretically also advance our understanding of potential alien life. If we can expand the base pairs of DNA in a lab on Earth successfully, maybe there's life out there with genetic materials with bases that are drastically different than anything we've observed thus far.

It's extremely fitting that the paper that led to this breakthrough was called "A Semi-Synthetic Organism with an Expanded Genetic Alphabet." Just adding the synthetic bases X and Y greatly expands the alphabet that spells out all life as we know it. The compounds that we would synthesize would truly be man-made.