Extending the genetic code

THE FUZZY specks growing on discs of jelly in Floyd Romesberg’s lab at Scripps Research in La Jolla look much like any other culture of E. coli. But appearances deceive—for the DNA of these bacteria is written in an alphabet that has six chemical letters instead of the usual four.

Extending the genetic code

THE FUZZY specks growing on discs of jelly in Floyd Romesberg’s lab at Scripps Research in La Jolla look much like any other culture of E. coli. But appearances deceive—for the DNA of these bacteria is written in an alphabet that has six chemical letters instead of the usual four.