Floyd Romesberg’s research combines the tools of bio/organic chemistry, molecular biology, microbiology, genetics, and modern spectroscopy to study different aspects of evolution. Projects include the identification and development of novel antibiotics; the development of tools to apply steady-state and time-resoved UV/vis and IR spectroscopy to understand how proteins are evolved for biological function; the investigation of the cellular response to DNA damage in prokaryotic and eukaryotic cells; and the development of unnatural base pairs with which to expand the genetic alphabet and thereby increase the chemical and functional potential of DNA and RNA. Recently Floyd’s lab succeeded in generating a semi-synthetic organism that stably propagates six-letter DNA, paving the way to living factories to produce novel proteins for biotechnological and medical applications. Floyd is also a co-founder of Achaogen, Inc., and RQx, Inc., two companies working to develop novel antibiotics, as well as Synthorx, Inc., a new synthetic biology company.