Genetic code of lab-made bacteria includes A, C, G, T and two synthetic molecules
Synthetic biologists have created the first living organism with a genetic code containing two artificial DNA bases in addition to the standard four letters: A, C, G and T.
The letters are the four DNA subunits, or nucleotides, which link together to make strings of genetic code. In most organisms, the nucleotides pair up (A’s with T’s and C’s with G’s), forming rungs of a twisted DNA ladder.
Floyd Romesberg of the Scripps Research Institute in La Jolla, Calif., and colleagues expanded the genetic language using a pair of synthetic nucleotides, called d5SICS and dNaM, which together make up a new rung of DNA.