Concept 18 Bacteria and viruses have DNA too.

Joshua Lederberg Alfred HersheyJoshua Lederberg was a Professor Emeritus at Rockefeller University, where his research addressed DNA conformation and evolutionary acceleration.
Al Hershey spent 47 years at Cold Spring Harbor Laboratory. Hershey was best known for his work, with Martha Chase, that showed that genes were made of DNA.

Joshua Lederberg