Your DNA, like that of everything else on the planet, is made of four nucleotides: A, C, G, and T. These are like a blueprint that your body reads to produce 20 different amino acids, which combine to make up the proteins that enable everything your body does, like repairing damaged cells or breaking down food.
Last year, biotech startup Synthorx announced that it had pushed the limits of biology by adding new building blocks to a bacteria’s genetic code. Now they’ve gone a step farther: those engineered bacteria have created a well-studied protein that has an added function, according to a press release the company issued yesterday. This could be the first step towards the discovery of new, more effective drugs and vaccines.
Synthorx added two more nucleotides, X and Y, to a bacteria’s DNA. These combine with the other four to make up to 172 different amino acids—over eight times the 20 commonly found in nature. These can combine to make an enormous number of proteins never before seen on Earth.